Fix editor focusing issues
- Autofocus needs to be evaluated before the switching promise is resolved (so callers can enable/disable autofocus after a switch) but executed after the switching promise is resolved (so callers that disable the editor while the promise is pending don't break)
- BoardDescriptionWidget makes itself pending (and disabled) for a longer period of time, so it needs to manually focus the editor when it un-disables it
Bug: T97290
Change-Id: Ic0fffc61a61503a7ceca714bfcb5e939c1966ec4