docs: Fix cURL example in get-user-groups.md.
docs: Fix cURL example in get-user-groups.md.

The issue here was that the endpoint was documented as being
contactable by bots when in reality we have a require_member_or_admin
decorator on the endpoint. So bots and guests cannot contact it.

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