Fix WebRequest concurrency test failing due to lack of list locking
Fix WebRequest concurrency test failing due to lack of list locking

smoogipooo/osu-framework,ppy/osu-framework,ZLima12/osu-framework,ZLima12/osu-framework,smoogipooo/osu-framework,peppy/osu-framework,EVAST9919/osu-framework,ppy/osu-framework,EVAST9919/osu-framework,peppy/osu-framework,ppy/osu-framework,EVAST9919/osu-framework,peppy/osu-framework,EVAST9919/osu-framework