Wrong files validation

I've found wrong call in SwaggerPageUI.php controller. "swagger-ui.jss" doesn't exist with double ss.

if (!drupal_verify_install_file('libraries/swagger-ui/dist/swagger-ui.jss', FILE_EXIST) && !drupal_verify_install_file($config->get('swagger_scan_output') . '/swagger.json', FILE_EXIST)) {
  drupal_set_message($this->t('Please contact the administrator.'), 'warning', FALSE);
  return [
    '#theme' => 'swagger_ui',
  ];
}