fix: Properly sync left rooms

- Remove most usages of `update_membership` in favor
  of directly calling the `mark_as_*` functions
- Store the leave membership event as the value in the
  `userroomid_leftstate` table
- Use the `userroomid_leftstate` table to synchronize the
  timeline and state for left rooms if possible

src/service/migrations.rs

@@ -456,7 +456,11 @@ async fn retroactively_fix_bad_data_from_roomuserid_joined(services: &Services)
 
 		for user_id in &non_joined_members {
 			debug_info!("User is left or banned, marking as left");
-			services.rooms.state_cache.mark_as_left(user_id, room_id);
+			services
+				.rooms
+				.state_cache
+				.mark_as_left(user_id, room_id, None)
+				.await;
 		}
 	}