message: Returning an empty list in case a room or layer is empty when deleting
diff: @@ -101,13 +101,13 @@ export function configureRoutes(app: express.Express, services: Services, option
  app.delete("/layers/:layerId/rooms/:roomId/users/:userId", validateLayerExists, validatePeerToken(getPeerJsRealm), (req, res, next) => {
  const { roomId, userId, layerId } = req.params;
  const room = layersService.getRoomsService(layerId)?.removeUserFromRoom(roomId, userId);
  - res.send(mapUsersToJson(room?.users));
  + res.send(mapUsersToJson(room?.users ?? []));
  });
  app.delete("/layers/:layerId/users/:userId", validateLayerExists, validatePeerToken(getPeerJsRealm), (req, res, next) => {
  const { userId, layerId } = req.params;
  const layer = layersService.removeUserFromLayer(layerId, userId);
  - res.send(mapUsersToJson(layer?.users));
  + res.send(mapUsersToJson(layer?.users ?? []));
  });
  app.get("/layers/:layerId/topology", validateLayerExists, (req, res, next) => {
  