mypy: Fix user_id typo in maybe_enqueue_notifications_for_message_update.
mypy: Fix user_id typo in maybe_enqueue_notifications_for_message_update.

This also lets us remove importing UserProfile at all in this module.

punchagan/zulip,hackerkid/zulip,rht/zulip,zulip/zulip,hackerkid/zulip,eeshangarg/zulip,andersk/zulip,eeshangarg/zulip,kou/zulip,kou/zulip,rht/zulip,andersk/zulip,zulip/zulip,rht/zulip,eeshangarg/zulip,kou/zulip,hackerkid/zulip,zulip/zulip,eeshangarg/zulip,zulip/zulip,hackerkid/zulip,zulip/zulip,rht/zulip,eeshangarg/zulip,andersk/zulip,kou/zulip,andersk/zulip,andersk/zulip,eeshangarg/zulip,punchagan/zulip,punchagan/zulip,hackerkid/zulip,zulip/zulip,punchagan/zulip,punchagan/zulip,andersk/zulip,rht/zulip,punchagan/zulip,rht/zulip,zulip/zulip,kou/zulip,andersk/zulip,hackerkid/zulip,punchagan/zulip,kou/zulip,eeshangarg/zulip,hackerkid/zulip,rht/zulip,kou/zulip