Join knock rooms on page load if already invited

[AndrewFerr]

When visiting the page for a knock room you are already invited to, join it right away instead of offering to knock (which will fail as long as you remain invited to the room).

[AndrewFerr]

Issue: when visiting a knock room & auto-joining it, the room header shows the room ID, not the room name. Does this mean a callback is missing somewhere?

[robintown]

Issue: when visiting a knock room & auto-joining it, the room header shows the room ID, not the room name. Does this mean a callback is missing somewhere?

Don't know about that one… in theory we update the name shown in the UI whenever the room emits a RoomEvent.Name event, so there could be a bug that matrix-js-sdk isn't signaling a name update in this case. Or, it's possible that there are multiple room objects floating around for the same room ID, and one of them is just a placeholder with only the room ID filled in. (that has happened before)

[AndrewFerr]

Eugh, there's something else funky about this. Despite joining the room, a joined user forever sees "Waiting for other participants…" even if other users have joined the call.

Putting this in draft until that's solved.

[AndrewFerr]

I did the sensible thing of testing the Netlify build of this instead of my local setup, and can reproduce not hitting the problem of a missing room name & getting stuck waiting for other call members.

At this point I'm inclined to believe those issues are unrelated to this PR, especially given how simple this PR is. So, I shall merge this.