MAGETWO-91307: Clean up typescript errors

- Resolved bamboo livecodetest failures

Author: Michael Yu

app/code/Magento/PageBuilder/Model/ContentType/DataProvider.php

@@ -3,6 +3,9 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+
+declare(strict_types=1);
+
 namespace Magento\PageBuilder\Model\ContentType;
 
 /**

dev/tests/integration/_files/Magento/TestModulePageBuilderDataMigration/Model/Attribute/ContentType.php

@@ -3,6 +3,9 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+
+declare(strict_types=1);
+
 namespace Magento\TestModulePageBuilderDataMigration\Model\Attribute;
 
 use Magento\Framework\Api\AttributeValueFactory;

dev/tests/integration/_files/Magento/TestModulePageBuilderDataMigration/Model/Install/ContentType.php

@@ -3,6 +3,9 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+
+declare(strict_types=1);
+
 namespace Magento\TestModulePageBuilderDataMigration\Model\Install;
 
 use Magento\TestModulePageBuilderDataMigration\Setup\EntitySetupFactory;

dev/tests/integration/_files/Magento/TestModulePageBuilderDataMigration/Model/ResourceModel/Attribute/ContentType.php

@@ -3,6 +3,9 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+
+declare(strict_types=1);
+
 namespace Magento\TestModulePageBuilderDataMigration\Model\ResourceModel\Attribute;
 
 class ContentType extends \Magento\Eav\Model\ResourceModel\Entity\Attribute\Set