accounts_register: Apply email_allowed_for_realm check to all code paths.
accounts_register: Apply email_allowed_for_realm check to all code paths.

Needed in case the user was allowed to join the realm when they got the
confirmation email, but is no longer allowed to do so. Check was previously
applied to invited users (those with a prereg_user.referred_by), and is now
applied regardless of how they get to accounts_register.

JPJPJPOPOP/zulip,amyliu345/zulip,joyhchen/zulip,jainayush975/zulip,Juanvulcano/zulip,zacps/zulip,ryanbackman/zulip,souravbadami/zulip,rishig/zulip,tommyip/zulip,kou/zulip,peguin40/zulip,ryanbackman/zulip,tommyip/zulip,souravbadami/zulip,timabbott/zulip,ryanbackman/zulip,jrowan/zulip,andersk/zulip,jackrzhang/zulip,showell/zulip,cosmicAsymmetry/zulip,synicalsyntax/zulip,isht3/zulip,vabs22/zulip,andersk/zulip,paxapy/zulip,Juanvulcano/zulip,KingxBanana/zulip,zacps/zulip,synicalsyntax/zulip,Diptanshu8/zulip,eeshangarg/zulip,brockwhittaker/zulip,souravbadami/zulip,arpith/zulip,eeshangarg/zulip,shubhamdhama/zulip,PhilSk/zulip,vabs22/zulip,jphilipsen05/zulip,peguin40/zulip,souravbadami/zulip,rishig/zulip,zulip/zulip,vikas-parashar/zulip,rht/zulip,calvinleenyc/zulip,samatdav/zulip,rht/zulip,arpith/zulip,sonali0901/zulip,PhilSk/zulip,Diptanshu8/zulip,jrowan/zulip,synicalsyntax/zulip,souravbadami/zulip,Juanvulcano/zulip,vaidap/zulip,andersk/zulip,hackerkid/zulip,tommyip/zulip,joyhchen/zulip,j831/zulip,arpith/zulip,dhcrzf/zulip,isht3/zulip,isht3/zulip,vikas-parashar/zulip,eeshangarg/zulip,rht/zulip,paxapy/zulip,jackrzhang/zulip,hackerkid/zulip,dhcrzf/zulip,punchagan/zulip,brockwhittaker/zulip,timabbott/zulip,isht3/zulip,susansls/zulip,dhcrzf/zulip,JPJPJPOPOP/zulip,sharmaeklavya2/zulip,Galexrt/zulip,aakash-cr7/zulip,dawran6/zulip,blaze225/zulip,mahim97/zulip,Jianchun1/zulip,peguin40/zulip,dattatreya303/zulip,grave-w-grave/zulip,TigorC/zulip,sharmaeklavya2/zulip,jainayush975/zulip,vikas-parashar/zulip,christi3k/zulip,tommyip/zulip,Diptanshu8/zulip,susansls/zulip,jackrzhang/zulip,christi3k/zulip,jainayush975/zulip,vaidap/zulip,timabbott/zulip,cosmicAsymmetry/zulip,dattatreya303/zulip,calvinleenyc/zulip,Galexrt/zulip,punchagan/zulip,Galexrt/zulip,amanharitsh123/zulip,punchagan/zulip,shubhamdhama/zulip,punchagan/zulip,Galexrt/zulip,shubhamdhama/zulip,joyhchen/zulip,brockwhittaker/zulip,vaidap/zulip,brainwane/zulip,rht/zulip,kou/zulip,blaze225/zulip,amanharitsh123/zulip,vikas-parashar/zulip,vikas-parashar/zulip,reyha/zulip,souravbadami/zulip,joyhchen/zulip,zulip/zulip,brainwane/zulip,tommyip/zulip,showell/zulip,showell/zulip,jainayush975/zulip,aakash-cr7/zulip,ryanbackman/zulip,zulip/zulip,amyliu345/zulip,PhilSk/zulip,mahim97/zulip,mahim97/zulip,andersk/zulip,brainwane/zulip,christi3k/zulip,Juanvulcano/zulip,dawran6/zulip,tommyip/zulip,dawran6/zulip,jrowan/zulip,TigorC/zulip,grave-w-grave/zulip,grave-w-grave/zulip,niftynei/zulip,calvinleenyc/zulip,hackerkid/zulip,timabbott/zulip,andersk/zulip,paxapy/zulip,eeshangarg/zulip,niftynei/zulip,brockwhittaker/zulip,jphilipsen05/zulip,jrowan/zulip,amyliu345/zulip,zacps/zulip,jphilipsen05/zulip,samatdav/zulip,TigorC/zulip,reyha/zulip,Galexrt/zulip,PhilSk/zulip,KingxBanana/zulip,Jianchun1/zulip,ryanbackman/zulip,vabs22/zulip,christi3k/zulip,JPJPJPOPOP/zulip,JPJPJPOPOP/zulip,showell/zulip,sharmaeklavya2/zulip,sonali0901/zulip,shubhamdhama/zulip,dattatreya303/zulip,susansls/zulip,brainwane/zulip,sharmaeklavya2/zulip,dawran6/zulip,christi3k/zulip,vabs22/zulip,Jianchun1/zulip,paxapy/zulip,jackrzhang/zulip,timabbott/zulip,Jianchun1/zulip,jphilipsen05/zulip,amyliu345/zulip,punchagan/zulip,dhcrzf/zulip,brainwane/zulip,TigorC/zulip,JPJPJPOPOP/zulip,zulip/zulip,niftynei/zulip,dattatreya303/zulip,niftynei/zulip,andersk/zulip,joyhchen/zulip,kou/zulip,punchagan/zulip,showell/zulip,dawran6/zulip,brainwane/zulip,arpith/zulip,SmartPeople/zulip,peguin40/zulip,susansls/zulip,synicalsyntax/zulip,amanharitsh123/zulip,grave-w-grave/zulip,dattatreya303/zulip,rishig/zulip,susansls/zulip,SmartPeople/zulip,j831/zulip,AZtheAsian/zulip,jainayush975/zulip,synicalsyntax/zulip,eeshangarg/zulip,TigorC/zulip,Diptanshu8/zulip,PhilSk/zulip,Jianchun1/zulip,Jianchun1/zulip,showell/zulip,reyha/zulip,zulip/zulip,timabbott/zulip,AZtheAsian/zulip,reyha/zulip,KingxBanana/zulip,calvinleenyc/zulip,amanharitsh123/zulip,shubhamdhama/zulip,peguin40/zulip,rishig/zulip,verma-varsha/zulip,rishig/zulip,dawran6/zulip,j831/zulip,mahim97/zulip,kou/zulip,amyliu345/zulip,susansls/zulip,amyliu345/zulip,jainayush975/zulip,aakash-cr7/zulip,calvinleenyc/zulip,Juanvulcano/zulip,ryanbackman/zulip,mahim97/zulip,sonali0901/zulip,AZtheAsian/zulip,shubhamdhama/zulip,synicalsyntax/zulip,rishig/zulip,niftynei/zulip,dhcrzf/zulip,grave-w-grave/zulip,vaidap/zulip,reyha/zulip,hackerkid/zulip,isht3/zulip,AZtheAsian/zulip,zacps/zulip,cosmicAsymmetry/zulip,synicalsyntax/zulip,kou/zulip,joyhchen/zulip,aakash-cr7/zulip,kou/zulip,brockwhittaker/zulip,KingxBanana/zulip,sonali0901/zulip,sharmaeklavya2/zulip,niftynei/zulip,calvinleenyc/zulip,arpith/zulip,blaze225/zulip,jrowan/zulip,rht/zulip,hackerkid/zulip,verma-varsha/zulip,AZtheAsian/zulip,Juanvulcano/zulip,vaidap/zulip,j831/zulip,amanharitsh123/zulip,grave-w-grave/zulip,brainwane/zulip,zulip/zulip,eeshangarg/zulip,vabs22/zulip,mahim97/zulip,zacps/zulip,zulip/zulip,zacps/zulip,aakash-cr7/zulip,jphilipsen05/zulip,rht/zulip,dhcrzf/zulip,KingxBanana/zulip,shubhamdhama/zulip,dattatreya303/zulip,jackrzhang/zulip,samatdav/zulip,brockwhittaker/zulip,verma-varsha/zulip,cosmicAsymmetry/zulip,PhilSk/zulip,jackrzhang/zulip,amanharitsh123/zulip,hackerkid/zulip,jrowan/zulip,Diptanshu8/zulip,showell/zulip,tommyip/zulip,cosmicAsymmetry/zulip,SmartPeople/zulip,verma-varsha/zulip,blaze225/zulip,andersk/zulip,reyha/zulip,rishig/zulip,hackerkid/zulip,cosmicAsymmetry/zulip,blaze225/zulip,kou/zulip,samatdav/zulip,KingxBanana/zulip,dhcrzf/zulip,JPJPJPOPOP/zulip,verma-varsha/zulip,arpith/zulip,verma-varsha/zulip,peguin40/zulip,samatdav/zulip,SmartPeople/zulip,vikas-parashar/zulip,paxapy/zulip,eeshangarg/zulip,j831/zulip,blaze225/zulip,samatdav/zulip,SmartPeople/zulip,rht/zulip,sharmaeklavya2/zulip,SmartPeople/zulip,Diptanshu8/zulip,j831/zulip,timabbott/zulip,jphilipsen05/zulip,aakash-cr7/zulip,jackrzhang/zulip,sonali0901/zulip,paxapy/zulip,isht3/zulip,vaidap/zulip,AZtheAsian/zulip,vabs22/zulip,Galexrt/zulip,punchagan/zulip,christi3k/zulip,Galexrt/zulip,TigorC/zulip,sonali0901/zulip