Fix PHP CS Fixer style in OrderController

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/Controller/OrderController.php

@@ -415,9 +415,6 @@ class OrderController extends AbstractController
         return min($qty, $billet->getQuantity());
     }
 
-    /**
-     * @param mixed $cart
-     */
     private function isValidCart(mixed $cart): bool
     {
         if (!\is_array($cart) || 0 === \count($cart)) {