dev_login: Don't redirect to realm if it doesn't exist.
dev_login: Don't redirect to realm if it doesn't exist.

Fixes #7132.

zulip/zulip,synicalsyntax/zulip,kou/zulip,kou/zulip,tommyip/zulip,shubhamdhama/zulip,hackerkid/zulip,showell/zulip,Galexrt/zulip,andersk/zulip,brainwane/zulip,punchagan/zulip,shubhamdhama/zulip,synicalsyntax/zulip,brainwane/zulip,mahim97/zulip,eeshangarg/zulip,brainwane/zulip,Galexrt/zulip,zulip/zulip,kou/zulip,rht/zulip,rishig/zulip,showell/zulip,tommyip/zulip,shubhamdhama/zulip,tommyip/zulip,synicalsyntax/zulip,brockwhittaker/zulip,kou/zulip,showell/zulip,kou/zulip,punchagan/zulip,zulip/zulip,brockwhittaker/zulip,dhcrzf/zulip,brockwhittaker/zulip,rishig/zulip,showell/zulip,synicalsyntax/zulip,Galexrt/zulip,timabbott/zulip,kou/zulip,hackerkid/zulip,shubhamdhama/zulip,jackrzhang/zulip,eeshangarg/zulip,showell/zulip,zulip/zulip,andersk/zulip,tommyip/zulip,rishig/zulip,Galexrt/zulip,andersk/zulip,hackerkid/zulip,zulip/zulip,punchagan/zulip,synicalsyntax/zulip,zulip/zulip,eeshangarg/zulip,synicalsyntax/zulip,mahim97/zulip,timabbott/zulip,jackrzhang/zulip,shubhamdhama/zulip,tommyip/zulip,Galexrt/zulip,tommyip/zulip,timabbott/zulip,timabbott/zulip,eeshangarg/zulip,jackrzhang/zulip,andersk/zulip,timabbott/zulip,mahim97/zulip,brainwane/zulip,mahim97/zulip,brockwhittaker/zulip,andersk/zulip,dhcrzf/zulip,tommyip/zulip,zulip/zulip,rishig/zulip,rishig/zulip,dhcrzf/zulip,jackrzhang/zulip,rht/zulip,timabbott/zulip,rht/zulip,brainwane/zulip,rht/zulip,punchagan/zulip,andersk/zulip,rishig/zulip,rht/zulip,showell/zulip,eeshangarg/zulip,hackerkid/zulip,rht/zulip,rishig/zulip,dhcrzf/zulip,shubhamdhama/zulip,Galexrt/zulip,hackerkid/zulip,Galexrt/zulip,synicalsyntax/zulip,timabbott/zulip,jackrzhang/zulip,dhcrzf/zulip,dhcrzf/zulip,punchagan/zulip,eeshangarg/zulip,jackrzhang/zulip,mahim97/zulip,brainwane/zulip,andersk/zulip,punchagan/zulip,brainwane/zulip,dhcrzf/zulip,showell/zulip,mahim97/zulip,brockwhittaker/zulip,hackerkid/zulip,punchagan/zulip,rht/zulip,jackrzhang/zulip,hackerkid/zulip,brockwhittaker/zulip,eeshangarg/zulip,shubhamdhama/zulip,kou/zulip