Fix validation bug on Nickname Clause
Fix validation bug on Nickname Clause

Pokémon without nicknames would trigger an error.
This commit fixes be4e41c2832fb700808b1f8c27fdbfdad711bf61

TheManwithskills/New-boiler-test,sirDonovan/Pokemon-Showdown,lAlejandro22/lolipoop,KewlStatics/Showdown-Template,ehk12/coregit,TheManwithskills/COC,MeliodasBH/Articuno-Land,Lauc1an/Perulink-Showdown,KewlStatics/Shit,ankailou/Pokemon-Showdown,MasterFloat/Pokemon-Showdown,SubZeroo99/Pokemon-Showdown,Irraquated/Pokemon-Showdown,Ransei1/Alt,SerperiorBae/Bae-Showdown-2,TheManwithskills/Dusk--Showdown,danpantry/Pokemon-Showdown,Flareninja/Pokemon-Showdown,Kill-The-Noise/BlakJack-Boilerplate,SSJGVegito007/Vegito-s-Server,PrimalGallade45/Lumen-Pokemon-Showdown,Zarel/Pokemon-Showdown,Nineage/Origin,jumbowhales/Pokemon-Showdown,psnsVGC/Wish-Server,theodelhay/test,MayukhKundu/Flame-Savior,svivian/Pokemon-Showdown,aakashrajput/Pokemon-Showdown,Legit99/Lightning-Storm-Server,EmmaKitty/Pokemon-Showdown,bai2/Dropp,Darkshadow6/PokeMoon-Creation,CreaturePhil/Pokemon-Showdown,KaitoV4X/Showdown,theodelhay/test,LegendBorned/PS-Boilerplate,Enigami/Pokemon-Showdown,Flareninja/Lumen-Pokemon-Showdown,kupochu/Pokemon-Showdown,svivian/Pokemon-Showdown,Alpha-Devs/Alpha-Server,gustavo515/gashoro,urkerab/Pokemon-Showdown,johtooo/PS,DesoGit/TsunamiPS,abrulochp/Lumen-Pokemon-Showdown,Flareninja/Showdown-Boilerplate,QuiteQuiet/Pokemon-Showdown,hayleysworld/serenityc9,DalleTest/Pokemon-Showdown,megaslowbro1/Pokemon-Showdown-Server-for-megaslowbro1,lFernanl/Pokemon-Showdown,Lord-Haji/SpacialGaze,KewlStatics/Alliance,DesoGit/Tsunami_PS,kuroscafe/Paradox,Celecitia/Plux-Pokemon-Showdown,SerperiorBae/Bae-Showdown,abrulochp/Dropp-Pokemon-Showdown,KewlStatics/Showdown-Template,asdfghjklohhnhn/Pokemon-Showdown,Elveman/RPCShowdownServer,JellalTheMage/Jellals-Server,hayleysworld/Showdown-Boilerplate,piiiikachuuu/Pokemon-Showdown,lFernanl/Zero-Pokemon-Showdown,JennyPRO/Jenny,PS-Spectral/Spectral,ehk12/coregit,Git-Worm/City-PS,Sora-Server/Sora,kubetz/Pokemon-Showdown,Zarel/Pokemon-Showdown,gustavo515/gashoro,EmmaKitty/Pokemon-Showdown,SerperiorBae/BaeShowdown,Zipzapadam/Server,kubetz/Pokemon-Showdown,yashagl/pokemon,TheManwithskills/Server,ZestOfLife/PSserver,UniversalMan12/Universe-Server,Kill-The-Noise/BlakJack-Boilerplate,QuiteQuiet/Pokemon-Showdown,panpawn/Gold-Server,Irraquated/EOS-Master,MayukhKundu/Flame-Savior,Bryan-0/Pokemon-Showdown,DB898/theregalias,bai2/Dropp,Zipzapadam/Server,Enigami/Pokemon-Showdown,ZestOfLife/PSserver,DarkSuicune/Kakuja-2.0,LightningStormServer/Lightning-Storm,Hidden-Mia/Roleplay-PS,Firestatics/omega,Darkshadow6/PokeMoon-Creation,zczd/enculer,cadaeic/Pokemon-Showdown,BuzzyOG/Pokemon-Showdown,hayleysworld/serenity,scotchkorean27/Pokemon-Showdown,urkerab/Pokemon-Showdown,k3naan/Pokemon-Showdown,Pikachuun/Pokemon-Showdown,CharizardtheFireMage/Showdown-Boilerplate,arkanox/MistShowdown,Nineage/Origin,Flareninja/Pokemon-Showdown,HoeenCoder/SpacialGaze,hayleysworld/harmonia,gustavo515/batata,BlazingAura/Showdown-Boilerplate,brettjbush/Pokemon-Showdown,MeliodasBH/boarhat,forbiddennightmare/Pokemon-Showdown-1,ehk12/bigbangtempclone,SerperiorBae/Pokemon-Showdown,JennyPRO/Jenny,MayukhKundu/Technogear-Final,SerperiorBae/Pokemon-Showdown-1,zek7rom/SpacialGaze,Pablo000/aaa,Kevinxzllz/PS-Openshift-Server,LustyAsh/EOS-Master,Volcos/SpacialGaze,xCrystal/Pokemon-Showdown,TheFenderStory/Showdown-Boilerplate,hayleysworld/Showdown-Boilerplate,Atwar/server-epilogueleague.rhcloud.com,CreaturePhil/Showdown-Boilerplate,Flareninja/Showdown-Boilerplate,svivian/Pokemon-Showdown,ankailou/Pokemon-Showdown,Irraquated/Pokemon-Showdown,SolarisFox/Pokemon-Showdown,FakeSloth/wulu,Darkshadow6/git-remote-add-scalingo-git-scalingo.com-pokemoonforums,Parukia/Pokemon-Showdown,Syurra/Pokemon-Showdown,piiiikachuuu/Pokemon-Showdown,sama2/Lumen-Pokemon-Showdown,Extradeath/psserver,TheFenderStory/Pokemon-Showdown,panpawn/Pokemon-Showdown,Mystifi/Exiled,Hidden-Mia/Roleplay-PS,Atwar/ServerClassroom,BuzzyOG/Pokemon-Showdown,MayukhKundu/Mudkip-Server,TheManwithskills/Dusk--Showdown,CreaturePhil/Showdown-Boilerplate,KewlStatics/Alliance,danpantry/Pokemon-Showdown,kotarou3/Krister-Pokemon-Showdown,Firestatics/Firestatics46,Tesarand/Pokemon-Showdown,SilverTactic/Dragotica-Pokemon-Showdown,UniversalMan12/Universe-Server,yashagl/pokecommunity,NoahVSGamingYT/Pokemon-Showdown,AWailOfATail/Pokemon-Showdown,SilverTactic/Dragotica-Pokemon-Showdown,yashagl/pokemon,MasterFloat/LQP-Server-Showdown,megaslowbro1/Pokemon-Showdown-Server-for-megaslowbro1,Celecitia/Plux-Pokemon-Showdown,SerperiorBae/Bae-Showdown,ShowdownHelper/Saffron,TheDiabolicGift/Showdown-Boilerplate,CreaturePhil/Showdown-Boilerplate,LightningStormServer/Lightning-Storm,InvalidDN/Pokemon-Showdown,johtooo/PS,Kevinxzllz/PS-Openshift-Server,SilverTactic/Showdown-Boilerplate,TheManwithskills/Creature-phil-boiler,PS-Spectral/Spectral,yashagl/pokecommunity,Ecuacion/Pokemon-Showdown,MeliodasBH/boarhat,SkyeTheFemaleSylveon/Pokemon-Showdown,panpawn/Gold-Server,Atwar/ServerClassroom,AustinXII/Pokemon-Showdown,ShowdownHelper/Saffron,AnaRitaTorres/Pokemon-Showdown,SSJGVegito007/Vegito-s-Server,Legit99/Lightning-Storm-Server,comedianchameleon/test,yashagl/yash-showdown,Darkshadow6/git-remote-add-scalingo-git-scalingo.com-pokemoonforums,SerperiorBae/Bae-Showdown-2,ZeroParadox/BlastBurners,hayleysworld/serenityc9,SerperiorBae/Pokemon-Showdown,hayleysworld/Pokemon-Showdown,Zarel/Pokemon-Showdown,superman8900/Pokemon-Showdown,AnaRitaTorres/Pokemon-Showdown,lFernanl/Lumen-Pokemon-Showdown,lFernanl/Mudkip-Server,MayukhKundu/Pokemon-Domain,PrimalGallade45/Lumen-Pokemon-Showdown,Darkshadow6/PokeMoon-Creation,megaslowbro1/Showdown-Server-again,KaitoV4X/Showdown,jd4564/Pokemon-Showdown,SolarisFox/Pokemon-Showdown,Ecuacion/Pokemon-Showdown,Articuno-I/Pokemon-Showdown,PrimalGallade45/Dropp-Pokemon-Showdown,hayleysworld/serenityserver,megaslowbro1/Pokemon-Showdown,sama2/Lumen-Pokemon-Showdown,Neosweiss/Pokemon-Showdown,BlazingAura/Showdown-Boilerplate,kuroscafe/Showdown-Boilerplate,DesoGit/Tsunami_PS,kupochu/Pokemon-Showdown,AWailOfATail/awoat,TheManwithskills/New-boiler-test,TheFenderStory/Showdown-Boilerplate,ZeroParadox/ugh,gustavo515/test,abrulochp/Lumen-Pokemon-Showdown,Lord-Haji/SpacialGaze,Firestatics/Omega-Alpha,ScottehMax/Pokemon-Showdown,DarkSuicune/Kakuja-2.0,TheDiabolicGift/Lumen-Pokemon-Showdown,Yggdrasil-League/Yggdrasil,Darkshadow6/git-remote-add-scalingo-git-scalingo.com-pokemoonforums,Sora-League/Sora,Kill-The-Noise/BlakJack-Boilerplate,Pablo000/aaa,Elveman/RPCShowdownServer,ehk12/clone,QuiteQuiet/Pokemon-Showdown,urkerab/Pokemon-Showdown,arkanox/MistShowdown,DarkSuicune/Pokemon-Showdown,Irraquated/Showdown-Boilerplate,Wando94/Pokemon-Showdown,TheManwithskills/Server---Thermal,Breakfastqueen/advanced,MayukhKundu/Technogear-Final,TheManwithskills/DS,KewlStatics/Pokeindia-Codes,DesoGit/Tsunami_PS,Wando94/Spite,Bryan-0/Pokemon-Showdown,SerperiorBae/Pokemon-Showdown,Lord-Haji/SpacialGaze,sama2/Dropp-Pokemon-Showdown,Alpha-Devs/OmegaRuby-Server,hayleysworld/asdfasdf,Alpha-Devs/OmegaRuby-Server,xfix/Pokemon-Showdown,lFernanl/Zero-Pokemon-Showdown,psnsVGC/Wish-Server,TbirdClanWish/Pokemon-Showdown,svivian/Pokemon-Showdown,SerperiorBae/Bae-Showdown-2,Alpha-Devs/Alpha-Server,LegendBorned/PS-Boilerplate,Volcos/SpacialGaze,xfix/Pokemon-Showdown,xCrystal/Pokemon-Showdown,BuzzyOG/Pokemon-Showdown,panpawn/Pokemon-Showdown,Sora-Server/Sora,Yggdrasil-League/Yggdrasil,MasterFloat/LQP-Server-Showdown,SerperiorBae/BaeShowdown,Ecuacion/Lumen-Pokemon-Showdown,anubhabsen/Pokemon-Showdown,Ecuacion/Lumen-Pokemon-Showdown,TheManwithskills/Creature-phil-boiler,Ridukuo/Test,Pikachuun/Pokemon-Showdown,svivian/Pokemon-Showdown,PS-Spectral/Spectral,Firestatics/Firestatics46,Git-Worm/City-PS,aakashrajput/Pokemon-Showdown,LustyAsh/EOS-Master,ehk12/bigbangtempclone,Sora-League/Sora,PrimalGallade45/Dropp-Pokemon-Showdown,SerperiorBae/Pokemon-Showdown-1,TogeSR/Lumen-Pokemon-Showdown,HoeenCoder/SpacialGaze,AWailOfATail/Pokemon-Showdown,sirDonovan/Pokemon-Showdown,SubZeroo99/Pokemon-Showdown,Breakfastqueen/advanced,anubhabsen/Pokemon-Showdown,MayukhKundu/Technogear,abulechu/Dropp-Pokemon-Showdown,RustServer/Pokemon-Showdown,Wando94/Spite,AustinXII/Pokemon-Showdown,TheManwithskills/Server,SkyeTheFemaleSylveon/Mudkip-Server,AWailOfATail/Pokemon-Showdown,brettjbush/Pokemon-Showdown,Irraquated/Showdown-Boilerplate,xfix/Pokemon-Showdown,TheManwithskills/DS,azum4roll/Pokemon-Showdown,ZestOfLife/FestiveLife,TheDiabolicGift/Lumen-Pokemon-Showdown,megaslowbro1/Showdown-Server-again,DB898/theregalias,Kokonoe-san/Glacia-PS,TheManwithskills/serenity,kuroscafe/Paradox,azum4roll/Pokemon-Showdown,xfix/Pokemon-Showdown,hayleysworld/Pokemon-Showdown,DalleTest/Pokemon-Showdown,Extradeath/advanced,abulechu/Lumen-Pokemon-Showdown,EienSeiryuu/Pokemon-Showdown,Irraquated/EOS-Master,KewlStatics/Shit,Sora-Server/Sora,superman8900/Pokemon-Showdown,DesoGit/TsunamiPS,MasterFloat/Pokemon-Showdown,JellalTheMage/Jellals-Server,yashagl/pokemon-showdown,Articuno-I/Pokemon-Showdown,Flareninja/Lumen-Pokemon-Showdown,jumbowhales/Pokemon-Showdown,JellalTheMage/PS-,Guernouille/Pokemon-Showdown,abulechu/Lumen-Pokemon-Showdown,zek7rom/SpacialGaze,xfix/Pokemon-Showdown,lFernanl/Lumen-Pokemon-Showdown,PauLucario/LQP-Server-Showdown,Vacate/Pokemon-Showdown,FakeSloth/Infinite,yashagl/yash-showdown,SkyeTheFemaleSylveon/Pokemon-Showdown,AbsolitoSweep/Absol-server,ehk12/clone,ZeroParadox/BlastBurners,lFernanl/Pokemon-Showdown,Pokemon-Devs/Pokemon-Showdown,gustavo515/test,xCrystal/Pokemon-Showdown,scotchkorean27/Pokemon-Showdown,TheFenderStory/Pokemon-Showdown,HoeenCoder/SpacialGaze,AustinXII/Pokemon-Showdown,abulechu/Dropp-Pokemon-Showdown,Ransei1/Alt,TogeSR/Lumen-Pokemon-Showdown,Parukia/Pokemon-Showdown,Pikachuun/Pokemon-Showdown-SMCMDM,forbiddennightmare/Pokemon-Showdown-1,Irraquated/Pokemon-Showdown,kotarou3/Krister-Pokemon-Showdown,miahjennatills/Pokemon-Showdown,javi501/Lumen-Pokemon-Showdown,Mystifi/Exiled,Kokonoe-san/Glacia-PS,cadaeic/Pokemon-Showdown,ZestOfLife/FestiveLife,FakeSloth/Infinite,NoahVSGamingYT/Pokemon-Showdown,DarkSuicune/Pokemon-Showdown,TheManwithskills/serenity,InvalidDN/Pokemon-Showdown,hayleysworld/serenity,sirDonovan/Pokemon-Showdown,TbirdClanWish/Pokemon-Showdown,UniversalMan12/Universe-Server,Wando94/Pokemon-Showdown,CreaturePhil/Pokemon-Showdown,javi501/Lumen-Pokemon-Showdown,Enigami/Pokemon-Showdown,JellalTheMage/PS-,ZeroParadox/ugh,Parukia/Pokemon-Showdown,ShowdownHelper/Saffron,Breakfastqueen/advanced,Firestatics/omega,Vacate/Pokemon-Showdown,Syurra/Pokemon-Showdown,Guernouille/Pokemon-Showdown,hayleysworld/asdfasdf,lAlejandro22/lolipoop,HoeenCoder/SpacialGaze,sama2/Universe-Pokemon-Showdown,sama2/Dropp-Pokemon-Showdown,SerperiorBae/Bae-Showdown,gustavo515/final,SerperiorBae/Pokemon-Showdown-1,Firestatics/Omega-Alpha,Tesarand/Pokemon-Showdown,ScottehMax/Pokemon-Showdown,SilverTactic/Showdown-Boilerplate,LightningStormServer/Lightning-Storm,megaslowbro1/Pokemon-Showdown,comedianchameleon/test,Ridukuo/Test,panpawn/Gold-Server,Pikachuun/Pokemon-Showdown-SMCMDM,Pokemon-Devs/Pokemon-Showdown,AbsolitoSweep/Absol-server,Extradeath/psserver,Tesarand/Pokemon-Showdown,gustavo515/batata,Neosweiss/Pokemon-Showdown,hayleysworld/harmonia,kuroscafe/Showdown-Boilerplate,k3naan/Pokemon-Showdown,hayleysworld/serenityserver,aakashrajput/Pokemon-Showdown,abrulochp/Dropp-Pokemon-Showdown,miahjennatills/Pokemon-Showdown,sama2/Universe-Pokemon-Showdown,EienSeiryuu/Pokemon-Showdown,Mystifi/Exiled,AWailOfATail/awoat,TheDiabolicGift/Showdown-Boilerplate,comedianchameleon/test,TheManwithskills/COC,Lauc1an/Perulink-Showdown,Sora-League/Sora,Atwar/server-epilogueleague.rhcloud.com,MayukhKundu/Technogear,TheManwithskills/Server---Thermal,jumbowhales/Pokemon-Showdown,yashagl/pokemon-showdown,asdfghjklohhnhn/Pokemon-Showdown,SkyeTheFemaleSylveon/Mudkip-Server,lFernanl/Mudkip-Server,MayukhKundu/Pokemon-Domain,PauLucario/LQP-Server-Showdown,Enigami/Pokemon-Showdown,CharizardtheFireMage/Showdown-Boilerplate,SerperiorBae/BaeShowdown,jd4564/Pokemon-Showdown,MayukhKundu/Mudkip-Server,Extradeath/advanced,zczd/enculer,gustavo515/final,MeliodasBH/Articuno-Land,KewlStatics/Pokeindia-Codes,RustServer/Pokemon-Showdown