It turns out this polling was necessary to get extra data that isn't
included in the main listing request. It was removed deemed useless, and
in order to fix the order of rooms changing when selecting a room.
Weirdly, I can't reproduce this happening any more, and on close
inspection of the code can't see how it could happen in the first place.
For now, let's revert this change and iterate from there, if/when the
same issue arises again.
I've discussed avoiding this second poll by potentially including more
data (just `user_id`s?) in the main listing request, but not 100% sure
on this - even if the returned data is minimal it's an extra join
server-side, which could cause performance issues for large numbers of
rooms.
Looks like this was just copy-paste without any thought into whether it
should exist. It really shouldn't exist.
This is a thing for the playlists system because the *whole system*
there relies on polling the web API to get updated information. In the
case of mutliplayer, we hand off all communications to the realtime
server at the point of joining the rooms.
The argument that this was there to do faster polling on the selection
isn't valid since the polling times were the same for both cases.
Closes#11348.
