feature: remove not needed use (#716)

Author: Simperfit

core/form-data.md

@@ -17,7 +17,6 @@ This decorator is able to denormalize posted form data to the target object. In
 
 namespace App\EventListener;
 
-use ApiPlatform\Core\Exception\RuntimeException;
 use ApiPlatform\Core\Util\RequestAttributesExtractor;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Event\GetResponseEvent;