Make adjustments based on the review

Co-authored-by: Joas Schilling <coding@schilljs.com>
Signed-off-by: Hamid Dehnavi <hamid.dev.pro@gmail.com>

apps/dashboard/lib/Controller/DashboardController.php

@@ -51,7 +51,7 @@ class DashboardController extends Controller {
 		private IEventDispatcher $eventDispatcher,
 		private IManager $dashboardManager,
 		private IConfig $config,
-		private string $userId,
+		private ?string $userId,
 	) {
 		parent::__construct($appName, $request);