auth: Fix GitHub test for invalid user account.
auth: Fix GitHub test for invalid user account.

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