Fix missing tile bug

The 'connecting' tile change meant that we could have tiles right
at the start of the call where we wouldn't have before, and in fact
could have tiles for other users before we even had a tile for ourself.
This threw off the logic for ordering tiles which had a special case
for 1:1 calling which assumed that one of the tiles in a 1:1 call was
the local user. In this case, this assumption wasn't true at the very
start of the call, so the tile orders got assigned incorrectly and then
persisted for the rest of the call.

Fixes https://github.com/vector-im/element-call/issues/694

src/room/useGroupCall.ts

@@ -51,7 +51,7 @@ export interface UseGroupCallReturnType {
   requestingScreenshare: boolean;
   isScreensharing: boolean;
   screenshareFeeds: CallFeed[];
-  localDesktopCapturerSourceId: string;
+  localDesktopCapturerSourceId: string; // XXX: This looks unused?
   participants: RoomMember[];
   hasLocalParticipant: boolean;
   unencryptedEventsFromUsers: Set<string>;