Make carousel item sorting stable
Make carousel item sorting stable

Migrate beatmap carousel item sorting from List<T>.Sort()
to IEnumerable<T>.OrderBy(), as the second variant is documented to be
a stable sorting algorithm. This allows for eliminating unnecessary
movement of carousel items occurring whenever any set of items is tied
when changing sorting criteria.

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