Add validate method to PersonIdentifierEngineInterface and related classes

- Introduced `validate` method in `PersonIdentifierEngineInterface`.
- Added `ValidIdentifierConstraint` to `PersonIdentifier` entity.
- Updated `PersonIdentifierWorker` to implement the new `validate` method.

src/Bundle/ChillPersonBundle/Tests/Serializer/Normalizer/PersonJsonDenormalizerTest.php

@@ -25,6 +25,7 @@ use libphonenumber\PhoneNumber;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
 use Symfony\Component\Serializer\Normalizer\AbstractNormalizer;
+use Symfony\Component\Validator\Context\ExecutionContextInterface;
 
 /**
  * @internal
@@ -79,6 +80,8 @@ final class PersonJsonDenormalizerTest extends TestCase
 
                         return '' === $content;
                     }
+
+                    public function validate(ExecutionContextInterface $context, PersonIdentifier $identifier, PersonIdentifierDefinition $definition): void {}
                 };
 
                 return new PersonIdentifierWorker($engine, $definition);