Fix disposal issues in ChatOverlay testcase
Fix disposal issues in ChatOverlay testcase

UselessToucan/osu,naoey/osu,UselessToucan/osu,peppy/osu,ppy/osu,ppy/osu,peppy/osu-new,EVAST9919/osu,DrabWeb/osu,smoogipoo/osu,smoogipoo/osu,johnneijzen/osu,NeoAdonis/osu,peppy/osu,2yangk23/osu,smoogipoo/osu,smoogipooo/osu,ZLima12/osu,ZLima12/osu,UselessToucan/osu,2yangk23/osu,EVAST9919/osu,naoey/osu,DrabWeb/osu,NeoAdonis/osu,ppy/osu,NeoAdonis/osu,naoey/osu,peppy/osu,johnneijzen/osu,DrabWeb/osu