[RoomManager] drop duplicate joining of entities

REF: 0437e1d03f89a058f97a8884e3532a9a58b68b9d
REF: 62be5e29e5232150e7063bc189c5ad8a1189f972
Signed-off-by: Jakob Ackermann <das7pad@outlook.com>

services/real-time/app/js/RoomManager.js

@@ -85,7 +85,6 @@ module.exports = {
         { client: client.id, entity, id, beforeCount },
         'client joined existing room'
       )
-      client.join(id)
       callback()
     }
   },