MC-11044: Address Core MTF Tests That Are Skipped By PageBuilder

Add class annotation and strict_types declaration

Author: danmooney2

dev/tests/functional/tests/app/Magento/PageBuilder/Mtf/App/State/PageBuilderHandler.php

@@ -3,11 +3,17 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+
+declare(strict_types=1);
+
 namespace Magento\PageBuilder\Mtf\App\State;
 
 use Magento\Mtf\App\State\AbstractState;
 use Magento\Mtf\App\State\StateHandlerInterface;
 
+/**
+ * MTF test observer for managing PageBuilder's state
+ */
 class PageBuilderHandler implements StateHandlerInterface
 {
     /**