test_counts: Remove custom user creation code.
test_counts: Remove custom user creation code.

Like the last commit, this avoids us needing to update this random
test class in the analytics subsystem when we adjust the UserProfile
model.

zulip/zulip,andersk/zulip,rht/zulip,zulip/zulip,zulip/zulip,shubhamdhama/zulip,kou/zulip,showell/zulip,hackerkid/zulip,hackerkid/zulip,andersk/zulip,timabbott/zulip,synicalsyntax/zulip,brainwane/zulip,showell/zulip,hackerkid/zulip,showell/zulip,eeshangarg/zulip,andersk/zulip,showell/zulip,rht/zulip,synicalsyntax/zulip,andersk/zulip,hackerkid/zulip,synicalsyntax/zulip,hackerkid/zulip,kou/zulip,synicalsyntax/zulip,synicalsyntax/zulip,shubhamdhama/zulip,zulip/zulip,eeshangarg/zulip,timabbott/zulip,timabbott/zulip,zulip/zulip,rht/zulip,punchagan/zulip,kou/zulip,punchagan/zulip,timabbott/zulip,synicalsyntax/zulip,showell/zulip,eeshangarg/zulip,brainwane/zulip,punchagan/zulip,eeshangarg/zulip,brainwane/zulip,rht/zulip,punchagan/zulip,brainwane/zulip,kou/zulip,rht/zulip,eeshangarg/zulip,shubhamdhama/zulip,punchagan/zulip,brainwane/zulip,timabbott/zulip,andersk/zulip,shubhamdhama/zulip,showell/zulip,andersk/zulip,shubhamdhama/zulip,rht/zulip,zulip/zulip,eeshangarg/zulip,hackerkid/zulip,shubhamdhama/zulip,shubhamdhama/zulip,andersk/zulip,kou/zulip,zulip/zulip,kou/zulip,eeshangarg/zulip,brainwane/zulip,synicalsyntax/zulip,rht/zulip,kou/zulip,timabbott/zulip,punchagan/zulip,punchagan/zulip,brainwane/zulip,showell/zulip,hackerkid/zulip,timabbott/zulip