test_realm_emoji: Remove redundant assertion.
test_realm_emoji: Remove redundant assertion.

This check was added in 495a8476be619efae1be11f9d8bce40cb9698c39.
Now that django-stubs finds that the left operand of the `and` will
always evaluates to `True`, so it makes sense to remove it.

Signed-off-by: Zixuan James Li <74923aee05c23ca90566381b5d6b0cd9451b6054@gmail.com>

zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip,andersk/zulip,rht/zulip,andersk/zulip,rht/zulip,zulip/zulip,rht/zulip,rht/zulip,rht/zulip,zulip/zulip,zulip/zulip,andersk/zulip,andersk/zulip,andersk/zulip,andersk/zulip,andersk/zulip,rht/zulip,rht/zulip