Fix leaderboard potentially displaying the wrong scores
Fix leaderboard potentially displaying the wrong scores

Closes #14762.

This class is ugly. I think the whole process should be clened up once
we have correctly-scheduled `SynchronizationContext`s. There's not much
saving it as long as all these interdispersed `Schedule`s around
required.

ppy/osu,ppy/osu,NeoAdonis/osu,peppy/osu,peppy/osu,peppy/osu-new,smoogipoo/osu,smoogipoo/osu,smoogipoo/osu,ppy/osu,smoogipooo/osu,NeoAdonis/osu,NeoAdonis/osu,peppy/osu