Due to non-deterministic test failures in TestSceneBeatmapCarousel, migrate the checkSelected helper step from AddAssert to AddUntilStep. This adds more leniency for performance-related issues while still checking the desired behaviour.
Also fixes one issue I spotted in BeatmapCarousel related to incorrectly holding a selection after new sets are loaded.
Just a couple of steps for added coverage in visual tests. Very on-the-surface, the unit tests are supposed to cover the gory details.
Revert commit of "Move BPM out of OnlineInfo"
# Conflicts: # osu.Game.Tests/Visual/SongSelect/TestScenePlaySongSelect.cs