Expand scope to include webforms

Webforms are not nodes. This project only works with nodes.

This approach worked for me, for others looking:

/**
 * Alters a node when it is cloned.
 *
 * @param \Drupal\node\NodeInterface $node
 *   The node being cloned.
 */
function MY_MODULE_cloned_node_alter(NodeInterface &$node) {
  // Check if the node has a 'webform' field and it's not empty.
  if ($node->hasField('webform') && !$node->webform->isEmpty()) {
    // Load the original webform.
    $webform_id = $node->get('webform')->target_id;
    $webform = \Drupal::entityTypeManager()->getStorage('webform')->load($webform_id);

    if ($webform) {
      /** @var \Drupal\webform\WebformInterface $duplicate */
      $duplicate = $webform->createDuplicate();

      // Set the new webform's ID and title.
      $duplicate->set('id', 'webform_' . uniqid());
      $duplicate->set('title', 'Clone of ' . $webform->label());

      // Note: The duplicate webform is saved before updating the node.
      $duplicate->save();

      // Associate the duplicated webform with the cloned node.
      // The node is saved later.
      $node->set('webform', $duplicate);
    }
  }
}