Adds components `ChannelListing` and `ChannelListing` item with visual
test. Essentially a more simplified version of the existing
`ChannelSelectionOverlay` component.
Correctly implements `IFilterable` behaviour to filter child channel
items. Channel joined state is based on the underlying `Joined` bindable
of the `Channel` class.
Channel join/leave events are exposed via `OnRequestJoin` and
`OnRequestLeave` events which should be handled by parent component.
Requires a cached `OverlayColourScheme` instance to be provided by the
parent overlay component when added.
This wasn't being used by osu-web, and included far too much unnecessary
data. Of note, `pp` and `ruleset_id` are also not strictly required, but
there's no harm in sending them so I've left them be for now.
I kinda liked this flow, but from multiple reports from users it
definitely seems in the way. We can revisit after the new design is
applied to song select.
Note that this means the tooltips also don't display. If it is preferred
that they should (arguable from a UX perspective, since I'd expect to be
able to click at that point) then the issue can be addressed using a
slightly different path (a few more lines - nothing too complex).
This reverts commit 8115a4bb8f.
Commit was cherrypicked out to a separate pull on a different merge
base, then reverted in that pull, so it should be reverted here too.