Draft: Resolve #3495440 "Declaration of drupalserializationnormalizeranynormalizernormalize"

Closes #3495440

• Adding "supportsNormalization" method to avoid exceptions as:

Symfony\Component\Serializer\Exception\NotNormalizableValueException: Could not normalize object of type "Drupal\Core\Menu\MenuLinkTreeElement", no supporting normalizer found. in Symfony\Component\Serializer\Serializer->normalize() (line 181 of /var/www/html/vendor/symfony/serializer/Serializer.php).

• updating the signature