Install config from config/install dir in update hook.

/**
 * Save the bulk delete action to config.
 */
function redirect_update_8104() {
  if (!Action::load('redirect_delete_action')) {
    $entity_type_manager = \Drupal::entityTypeManager();
    $module_handler = \Drupal::moduleHandler();

    // Save the bulk delete action to config.
    $config_install_path = $module_handler->getModule('redirect')->getPath() . '/' . InstallStorage::CONFIG_INSTALL_DIRECTORY;
    $storage = new FileStorage($config_install_path);
    $entity_type_manager
      ->getStorage('action')
      ->create($storage->read('system.action.redirect_delete_action'))
      ->trustData()
      ->save();
  }
}