Avoid adding null users to `RecentParticipants`
Avoid adding null users to `RecentParticipants`

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