Using stream_id in recipient comparisons fixes a
bug in this scenario: go to home view, send message
to stream, wait for admin to rename stream, send
another message to the stream. Before this change,
the stream name would live-update but you'd get a
spurious recipient bar due to the prior message still
having the old stream name in places internally.
There were other ways to fix the live-update glitch,
but it's just generally cleaner to do stream id
comparisons.
Part of this change is to add stream_id to
compose_fade.set_focused_recipient().