Fix dialoged pushed to `DialogOverlay` too early potentially doing cross-thread transforms
Fix dialoged pushed to `DialogOverlay` too early potentially doing cross-thread transforms

As seen at https://github.com/ppy/osu/runs/6287700705?check_suite_focus=true.

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