The taiko-slider is not included in `Playfield`, so it doesn't get hidden when calling `drawableRuleSet.Playfield.Hide()`. Calling `drawableRuleSet.Hide()` hides the taiko-slider, in addition to the rest of the `Playfield`.
Not the most robust of fixes, but as per the reasoning described in the
issue thread, a proper fix will take considerably more effort. This
intends to fix the issue first and foremost, as it sounds so bad I'd
want to mute my sound before adjusting currently.
Closes#15718.
Was spiritually removed in https://github.com/ppy/osu/pull/16045.
This implementation is mostly taken from that PR's comment thread
verbatim, and now works due to the associated changes to
`OnlinePlayBeatmapAvailabilityTracker`.