Fix potential crash from cross-thread drawable mutation in collection management
Fix potential crash from cross-thread drawable mutation in collection management

As seen at https://github.com/peppy/osu/runs/4613800663?check_suite_focus=true.

peppy/osu,peppy/osu,NeoAdonis/osu,NeoAdonis/osu,ppy/osu,peppy/osu,NeoAdonis/osu,ppy/osu,ppy/osu