fix(validation): ValidationException causes TypeError exception when …

…called with $code=null (#6375)

src/Validator/Exception/ValidationException.php

@@ -81,7 +81,7 @@ public function __construct(string|ConstraintViolationListInterface $message = '
         }
 
         trigger_deprecation('api_platform/core', '3.3', sprintf('The "%s" exception will have a "%s" first argument in 4.x.', self::class, ConstraintViolationListInterface::class));
-        parent::__construct($message ?: $this->__toString(), $code, $previous);
+        parent::__construct($message ?: $this->__toString(), $code ?? 0, $previous);
     }
 
     /**