Default to quantity 1 in `order.contents.add`
Default to quantity 1 in `order.contents.add`

[Closes #3606]

freerunningtech/spree,shaywood2/spree,tomash/spree,xuewenfei/solidus,pervino/solidus,locomotivapro/spree,tomash/spree,welitonfreitas/spree,gregoryrikson/spree-sample,reidblomquist/spree,CiscoCloud/spree,jimblesm/spree,athal7/solidus,xuewenfei/solidus,firman/spree,azranel/spree,jasonfb/spree,raow/spree,zaeznet/spree,TimurTarasenko/spree,woboinc/spree,hifly/spree,FadliKun/spree,CiscoCloud/spree,vinsol/spree,vulk/spree,TimurTarasenko/spree,edgward/spree,Hawaiideveloper/shoppingcart,bricesanchez/spree,devilcoders/solidus,ckk-scratch/solidus,imella/spree,bjornlinder/Spree,zaeznet/spree,dotandbo/spree,mindvolt/spree,jaspreet21anand/spree,FadliKun/spree,Ropeney/spree,ahmetabdi/spree,woboinc/spree,lsirivong/spree,LBRapid/spree,grzlus/spree,locomotivapro/spree,useiichi/spree,lsirivong/spree,piousbox/spree,LBRapid/spree,quentinuys/spree,njerrywerry/spree,vmatekole/spree,tailic/spree,athal7/solidus,karlitxo/spree,PhoenixTeam/spree_phoenix,yushine/spree,knuepwebdev/FloatTubeRodHolders,DarkoP/spree,jspizziri/spree,Nevensoft/spree,trigrass2/spree,carlesjove/spree,CJMrozek/spree,keatonrow/spree,piousbox/spree,madetech/spree,moneyspyder/spree,alepore/spree,delphsoft/spree-store-ballchair,priyank-gupta/spree,zamiang/spree,Engeltj/spree,alejandromangione/spree,Mayvenn/spree,quentinuys/spree,CJMrozek/spree,Arpsara/solidus,yiqing95/spree,raow/spree,patdec/spree,rakibulislam/spree,jparr/spree,softr8/spree,beni55/spree,abhishekjain16/spree,jimblesm/spree,brchristian/spree,miyazawatomoka/spree,pervino/spree,builtbybuffalo/spree,jaspreet21anand/spree,scottcrawford03/solidus,groundctrl/spree,softr8/spree,radarseesradar/spree,alejandromangione/spree,odk211/spree,JDutil/spree,archSeer/spree,thogg4/spree,jasonfb/spree,welitonfreitas/spree,patdec/spree,lsirivong/spree,ahmetabdi/spree,Machpowersystems/spree_mach,Arpsara/solidus,sfcgeorge/spree,camelmasa/spree,vmatekole/spree,priyank-gupta/spree,assembledbrands/spree,archSeer/spree,DynamoMTL/spree,tesserakt/clean_spree,Boomkat/spree,net2b/spree,shioyama/spree,SadTreeFriends/spree,grzlus/spree,orenf/spree,richardnuno/solidus,rbngzlv/spree,pervino/solidus,jaspreet21anand/spree,welitonfreitas/spree,yushine/spree,jaspreet21anand/spree,Hawaiideveloper/shoppingcart,trigrass2/spree,AgilTec/spree,alepore/spree,freerunningtech/spree,madetech/spree,madetech/spree,beni55/spree,jspizziri/spree,joanblake/spree,useiichi/spree,jimblesm/spree,madetech/spree,agient/agientstorefront,assembledbrands/spree,fahidnasir/spree,sideci-sample/sideci-sample-spree,jordan-brough/solidus,Migweld/spree,edgward/spree,vinsol/spree,Nevensoft/spree,ayb/spree,vcavallo/spree,builtbybuffalo/spree,karlitxo/spree,yiqing95/spree,RatioClothing/spree,volpejoaquin/spree,useiichi/spree,zamiang/spree,alvinjean/spree,progsri/spree,pervino/spree,azranel/spree,Ropeney/spree,keatonrow/spree,StemboltHQ/spree,woboinc/spree,abhishekjain16/spree,azranel/spree,robodisco/spree,calvinl/spree,zaeznet/spree,Migweld/spree,PhoenixTeam/spree_phoenix,Kagetsuki/spree,derekluo/spree,carlesjove/spree,pjmj777/spree,Mayvenn/spree,shioyama/spree,jasonfb/spree,yomishra/pce,forkata/solidus,richardnuno/solidus,jsurdilla/solidus,sfcgeorge/spree,yiqing95/spree,Mayvenn/spree,zamiang/spree,fahidnasir/spree,maybii/spree,carlesjove/spree,Mayvenn/spree,keatonrow/spree,quentinuys/spree,adaddeo/spree,moneyspyder/spree,tomash/spree,CiscoCloud/spree,DarkoP/spree,KMikhaylovCTG/spree,tancnle/spree,Lostmyname/spree,moneyspyder/spree,joanblake/spree,vulk/spree,hoanghiep90/spree,miyazawatomoka/spree,project-eutopia/spree,softr8/spree,DarkoP/spree,grzlus/solidus,jparr/spree,shekibobo/spree,tesserakt/clean_spree,lsirivong/spree,Hawaiideveloper/shoppingcart,scottcrawford03/solidus,JDutil/spree,azclick/spree,pervino/solidus,wolfieorama/spree,Kagetsuki/spree,PhoenixTeam/spree_phoenix,fahidnasir/spree,delphsoft/spree-store-ballchair,camelmasa/spree,vinayvinsol/spree,bjornlinder/Spree,Boomkat/spree,tancnle/spree,yushine/spree,TimurTarasenko/spree,thogg4/spree,carlesjove/spree,imella/spree,KMikhaylovCTG/spree,rajeevriitm/spree,mleglise/spree,cutefrank/spree,tailic/spree,agient/agientstorefront,forkata/solidus,brchristian/spree,radarseesradar/spree,volpejoaquin/spree,degica/spree,vcavallo/spree,mleglise/spree,rakibulislam/spree,pjmj777/spree,robodisco/spree,ckk-scratch/solidus,DynamoMTL/spree,azclick/spree,Senjai/spree,omarsar/spree,Lostmyname/spree,caiqinghua/spree,SadTreeFriends/spree,APohio/spree,kewaunited/spree,omarsar/spree,athal7/solidus,bonobos/solidus,dandanwei/spree,bricesanchez/spree,sunny2601/spree,bonobos/solidus,APohio/spree,NerdsvilleCEO/spree,wolfieorama/spree,mleglise/spree,bonobos/solidus,sideci-sample/sideci-sample-spree,derekluo/spree,project-eutopia/spree,maybii/spree,mindvolt/spree,hoanghiep90/spree,beni55/spree,nooysters/spree,vmatekole/spree,jeffboulet/spree,Machpowersystems/spree_mach,jordan-brough/spree,firman/spree,alepore/spree,CiscoCloud/spree,jordan-brough/solidus,ayb/spree,vinayvinsol/spree,grzlus/spree,gautamsawhney/spree,Hates/spree,sliaquat/spree,groundctrl/spree,progsri/spree,vinayvinsol/spree,athal7/solidus,gregoryrikson/spree-sample,agient/agientstorefront,caiqinghua/spree,tailic/spree,maybii/spree,locomotivapro/spree,Nevensoft/spree,pervino/spree,derekluo/spree,Migweld/spree,Senjai/solidus,tesserakt/clean_spree,moneyspyder/spree,kitwalker12/spree,NerdsvilleCEO/spree,brchristian/spree,Engeltj/spree,lyzxsc/spree,useiichi/spree,yushine/spree,firman/spree,Kagetsuki/spree,hoanghiep90/spree,sideci-sample/sideci-sample-spree,Senjai/solidus,CJMrozek/spree,Arpsara/solidus,jeffboulet/spree,sliaquat/spree,gautamsawhney/spree,TrialGuides/spree,camelmasa/spree,berkes/spree,caiqinghua/spree,TrialGuides/spree,Ropeney/spree,surfdome/spree,grzlus/spree,jparr/spree,rajeevriitm/spree,rbngzlv/spree,ahmetabdi/spree,joanblake/spree,shaywood2/spree,joanblake/spree,xuewenfei/solidus,Hates/spree,surfdome/spree,alejandromangione/spree,shekibobo/spree,shaywood2/spree,devilcoders/solidus,sunny2601/spree,reinaris/spree,knuepwebdev/FloatTubeRodHolders,robodisco/spree,forkata/solidus,softr8/spree,dafontaine/spree,quentinuys/spree,vcavallo/spree,yomishra/pce,tancnle/spree,APohio/spree,LBRapid/spree,shekibobo/spree,lsirivong/solidus,jordan-brough/solidus,Nevensoft/spree,ayb/spree,biagidp/spree,net2b/spree,Senjai/spree,sfcgeorge/spree,thogg4/spree,siddharth28/spree,gautamsawhney/spree,beni55/spree,zamiang/spree,dandanwei/spree,progsri/spree,RatioClothing/spree,archSeer/spree,kewaunited/spree,piousbox/spree,JuandGirald/spree,abhishekjain16/spree,rakibulislam/spree,ramkumar-kr/spree,FadliKun/spree,lsirivong/solidus,gregoryrikson/spree-sample,JuandGirald/spree,adaddeo/spree,radarseesradar/spree,grzlus/solidus,richardnuno/solidus,NerdsvilleCEO/spree,calvinl/spree,jspizziri/spree,alvinjean/spree,ramkumar-kr/spree,StemboltHQ/spree,jspizziri/spree,raow/spree,jsurdilla/solidus,surfdome/spree,Arpsara/solidus,DynamoMTL/spree,caiqinghua/spree,reidblomquist/spree,degica/spree,volpejoaquin/spree,forkata/solidus,AgilTec/spree,vinsol/spree,hifly/spree,dotandbo/spree,trigrass2/spree,hoanghiep90/spree,bricesanchez/spree,ahmetabdi/spree,shekibobo/spree,JDutil/spree,rbngzlv/spree,orenf/spree,lsirivong/solidus,patdec/spree,ramkumar-kr/spree,Kagetsuki/spree,njerrywerry/spree,pjmj777/spree,miyazawatomoka/spree,Hawaiideveloper/shoppingcart,piousbox/spree,imella/spree,hifly/spree,ujai/spree,jordan-brough/spree,Hates/spree,mleglise/spree,degica/spree,grzlus/solidus,net2b/spree,rajeevriitm/spree,jasonfb/spree,azclick/spree,builtbybuffalo/spree,priyank-gupta/spree,adaddeo/spree,wolfieorama/spree,ujai/spree,reidblomquist/spree,miyazawatomoka/spree,maybii/spree,delphsoft/spree-store-ballchair,watg/spree,kewaunited/spree,Engeltj/spree,StemboltHQ/spree,alejandromangione/spree,ckk-scratch/solidus,nooysters/spree,raow/spree,brchristian/spree,dafontaine/spree,sliaquat/spree,jeffboulet/spree,Machpowersystems/spree_mach,pulkit21/spree,kitwalker12/spree,yomishra/pce,vcavallo/spree,jimblesm/spree,Hates/spree,reinaris/spree,dotandbo/spree,Senjai/solidus,tomash/spree,RatioClothing/spree,dafontaine/spree,siddharth28/spree,hifly/spree,xuewenfei/solidus,agient/agientstorefront,azranel/spree,reidblomquist/spree,gregoryrikson/spree-sample,project-eutopia/spree,ujai/spree,patdec/spree,mindvolt/spree,zaeznet/spree,yiqing95/spree,lyzxsc/spree,berkes/spree,jsurdilla/solidus,jhawthorn/spree,nooysters/spree,jparr/spree,groundctrl/spree,priyank-gupta/spree,freerunningtech/spree,delphsoft/spree-store-ballchair,azclick/spree,orenf/spree,pulkit21/spree,njerrywerry/spree,dandanwei/spree,vinsol/spree,Lostmyname/spree,progsri/spree,archSeer/spree,ayb/spree,njerrywerry/spree,orenf/spree,sliaquat/spree,JuandGirald/spree,Migweld/spree,kitwalker12/spree,cutefrank/spree,rbngzlv/spree,tancnle/spree,DynamoMTL/spree,mindvolt/spree,devilcoders/solidus,ckk-scratch/solidus,calvinl/spree,assembledbrands/spree,AgilTec/spree,adaddeo/spree,rakibulislam/spree,wolfieorama/spree,berkes/spree,DarkoP/spree,odk211/spree,biagidp/spree,trigrass2/spree,builtbybuffalo/spree,omarsar/spree,jordan-brough/solidus,cutefrank/spree,pulkit21/spree,groundctrl/spree,sfcgeorge/spree,jordan-brough/spree,volpejoaquin/spree,shaywood2/spree,lyzxsc/spree,pervino/spree,reinaris/spree,robodisco/spree,karlitxo/spree,dafontaine/spree,reinaris/spree,Boomkat/spree,TrialGuides/spree,omarsar/spree,alvinjean/spree,bonobos/solidus,lyzxsc/spree,vmatekole/spree,Senjai/spree,locomotivapro/spree,sunny2601/spree,Senjai/solidus,rajeevriitm/spree,berkes/spree,scottcrawford03/solidus,JuandGirald/spree,biagidp/spree,welitonfreitas/spree,KMikhaylovCTG/spree,KMikhaylovCTG/spree,pervino/solidus,alvinjean/spree,fahidnasir/spree,jhawthorn/spree,ramkumar-kr/spree,bjornlinder/Spree,odk211/spree,project-eutopia/spree,cutefrank/spree,siddharth28/spree,jeffboulet/spree,APohio/spree,SadTreeFriends/spree,Ropeney/spree,AgilTec/spree,Lostmyname/spree,surfdome/spree,gautamsawhney/spree,PhoenixTeam/spree_phoenix,edgward/spree,watg/spree,watg/spree,TrialGuides/spree,grzlus/solidus,devilcoders/solidus,jhawthorn/spree,CJMrozek/spree,NerdsvilleCEO/spree,jsurdilla/solidus,keatonrow/spree,thogg4/spree,odk211/spree,radarseesradar/spree,firman/spree,tesserakt/clean_spree,richardnuno/solidus,edgward/spree,karlitxo/spree,Boomkat/spree,kewaunited/spree,nooysters/spree,knuepwebdev/FloatTubeRodHolders,vulk/spree,shioyama/spree,JDutil/spree,sunny2601/spree,lsirivong/solidus,vulk/spree,abhishekjain16/spree,FadliKun/spree,derekluo/spree,siddharth28/spree,pulkit21/spree,camelmasa/spree,net2b/spree,Engeltj/spree,calvinl/spree,dotandbo/spree,scottcrawford03/solidus,TimurTarasenko/spree,vinayvinsol/spree,SadTreeFriends/spree,dandanwei/spree