[Validator] Fix regression with class metadatada on parent classes

Author: rmikalkenas

Validator/DoctrineLoader.php

@@ -108,7 +108,7 @@ public function loadClassMetadata(ClassMetadata $metadata): bool
                 if (isset($mapping['originalClass']) && !str_contains($mapping['declaredField'], '.')) {
                     $metadata->addPropertyConstraint($mapping['declaredField'], new Valid());
                     $loaded = true;
-                } elseif (property_exists($className, $mapping['fieldName'])) {
+                } elseif (property_exists($className, $mapping['fieldName']) && (!$doctrineMetadata->isMappedSuperclass || $metadata->getReflectionClass()->getProperty($mapping['fieldName'])->isPrivate())) {
                     $metadata->addPropertyConstraint($mapping['fieldName'], new Length(['max' => $mapping['length']]));
                     $loaded = true;
                 }