Make opening chat overlay opt-in to add coverage for unloaded chat overlays
Make opening chat overlay opt-in to add coverage for unloaded chat overlays

Causes `TestHighlightWhileChatNeverOpen` to fail as expected.

ppy/osu,NeoAdonis/osu,NeoAdonis/osu,ppy/osu,NeoAdonis/osu,peppy/osu,ppy/osu,peppy/osu,peppy/osu