MenuEntityCloneForm.php

<?php

namespace Drupal\entity_clone\EntityClone\Config;

use Drupal\Core\Entity\EntityInterface;

/**
 * Class Menu Entity Clone Form.
 */
class MenuEntityCloneForm extends ConfigEntityCloneFormBase {
    
    /**
     * {@inheritdoc}
     */
    public function formElement(EntityInterface $entity, $parent = TRUE) {
        $form = parent::formElement($entity, $parent);
        // Menu entities require special replace pattern.
        $form['id']['#machine_name'] += [
            'replace_pattern' => '[^a-z0-9-]+',
            'replace' => '-',
        ];
        return $form;
    }

}