This commit changes stream_data.in_home_view() to
take a stream_id parameter, which will make it more
robust to stream name changes.
This fixes a bug. Now when an admin renames a stream
you are looking at, it will correctly show itself to
be un-muted. (Even with this fix, though, the stream
appears to be inactive.)
Some callers still do lookups by name, and they will
call name_in_home_view() for now, which we can
hopefully deprecate over time.