AC-11610: Catalog Search fix

   * Strict type declaration

Author: faraz-gl

app/code/Magento/AdvancedSearch/Controller/Adminhtml/Search/System/Config/TestConnection.php

@@ -4,6 +4,8 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+declare(strict_types=1);
+
 namespace Magento\AdvancedSearch\Controller\Adminhtml\Search\System\Config;
 
 use Magento\Backend\App\Action;