Fix Gigantamax formes being available in past gens
Fix Gigantamax formes being available in past gens

A WIP Gigantamax implementation broke this.

Fixes #5961

xfix/Pokemon-Showdown,Zarel/Pokemon-Showdown,Enigami/Pokemon-Showdown,svivian/Pokemon-Showdown,Enigami/Pokemon-Showdown,AustinXII/Pokemon-Showdown,Zarel/Pokemon-Showdown,QuiteQuiet/Pokemon-Showdown,jumbowhales/Pokemon-Showdown,svivian/Pokemon-Showdown,Enigami/Pokemon-Showdown,Enigami/Pokemon-Showdown,jumbowhales/Pokemon-Showdown,xfix/Pokemon-Showdown,sirDonovan/Pokemon-Showdown,urkerab/Pokemon-Showdown,xfix/Pokemon-Showdown,xfix/Pokemon-Showdown,QuiteQuiet/Pokemon-Showdown,QuiteQuiet/Pokemon-Showdown,urkerab/Pokemon-Showdown,xfix/Pokemon-Showdown,AustinXII/Pokemon-Showdown,svivian/Pokemon-Showdown,svivian/Pokemon-Showdown,Zarel/Pokemon-Showdown,sirDonovan/Pokemon-Showdown,svivian/Pokemon-Showdown,sirDonovan/Pokemon-Showdown,urkerab/Pokemon-Showdown,jumbowhales/Pokemon-Showdown,AustinXII/Pokemon-Showdown