Set local echoes as room last events

TODO.md

@@ -39,7 +39,6 @@
 
   - Combine events so they take less space
     - After combining is implemented, no need to hide our own profile changes.
-  - Room last activity time in RoomDelegate
   - When starting a long task, e.g. importing keys, quitting the page,
     and coming back, show the buttons as still loading until operation is done
   - Make invite/left banners look better in column mode

src/python/matrix_client.py

@@ -198,6 +198,8 @@ class MatrixClient(nio.AsyncClient):
             if user_id in self.models[Member, room_id]:
                 self.models[Event, user_id, room_id][f"echo-{uuid}"] = local
 
+        await self.set_room_last_event(room_id, local)
+
         async with self.send_locks[room_id]:
             response = await self.room_send(
                 room_id                   = room_id,