fix media sync thinking >25 changes is a concurrent update
fix media sync thinking >25 changes is a concurrent update

holycrepe/anki,xuewenfei/anki,Stvad/anki,socialpercon/anki-1,subfusc/anki,florianjacob/anki,Arthaey/anki,eduOS/anki,jakesyl/ruby-card,kenjhim/anki,weihautin/anki,ospalh/libanki3,jakesyl/ruby-card,jkitching/anki,weihautin/anki,hssm/anki,sunclx/anki,LucasCabello/anki,go38/anki,abeyer/anki,hssm/anki