Cron fails on amazon_ses when not configured

I have a patch for a work-around, but I'm not sure if this isn't a bad idea :-)

class AmazonSesMailQueue extends QueueWorkerBase implements ContainerFactoryPluginInterface {
  use HandlerTrait;

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    $instance = new static(
      $configuration,
      $plugin_id,
      $plugin_definition
    );

    // Only set the handler if queueing is enabled to avoid an error when
    // trying to run without config.
    $enabled = \Drupal::config('amazon_ses.settings')->get('queue');
    if ($enabled) {
      $instance->setHandler($container->get('amazon_ses.handler'));
    }

    return $instance;
  }

davisben → changed the visibility of the branch 3417090 to hidden.

I took a different approach by implementing hook_queue_info_alter() to remove the mail queue from cron when it's not enabled. Could you give this a test and see if it works as you expect it to?