[CodeQuality] Skip loadValidatorMetadata() containing addConstraint(new Callback())

[TomasVotruba]

A Callback constraint wraps a closure or a method reference. It cannot be expressed as constant attribute arguments, so moving the surrounding constraints out and leaving (or converting) the Callback breaks validation.

Now LoadValidatorMetadataToAttributeRector leaves the whole loadValidatorMetadata() method untouched when it contains $metadata->addConstraint(new Callback(...)).

Before this change, a Callback class constraint was converted to a class attribute:

-final class SomeClass
-{
-    public static function loadValidatorMetadata(ClassMetadata $metadata): void
-    {
-        $metadata->addConstraint(new Assert\Callback('validatePostalCode'));
-    }
-}
+#[\Symfony\Component\Validator\Constraints\Callback('validatePostalCode')]
+final class SomeClass
+{
+}

Now such a method is skipped entirely — no change — including when a movable constraint sits beside the Callback:

// left untouched
public static function loadValidatorMetadata(ClassMetadata $metadata): void
{
    $metadata->addPropertyConstraint('city', new Assert\NotBlank());
    $metadata->addConstraint(new Assert\Callback('validateCity'));
}