Don’t let capability discovery block room joins

Issues
1

Parent: #680

An unanswered caps request blocks presence processing, so even though the server thinks we’ve joined, our local state still says isJoined: false. The app remains stuck syncing with outgoing messages paused.

2

Child ticket: #736

3

https://lists.sr.ht/~singpolyma/borogove/<3c965b89-0daf-4a46-817a-55aa2a5fff9c@devl.me>

4

84aaafc0d66d4fa787e43b947c38a6e542ffb42f