Moved test to the folder that suits naming convention

Author: TomashKhamlai

dev/tests/api-functional/testsuite/Magento/GraphQl/Downloadable/CustomerDownloadableProductsTest.php renamed to dev/tests/api-functional/testsuite/Magento/GraphQl/DownloadableProduct/CustomerDownloadableProductsTest.php

@@ -5,7 +5,7 @@
  */
 declare(strict_types=1);
 
-namespace Magento\GraphQl\Downloadable;
+namespace Magento\GraphQl\DownloadableProduct;
 
 use Magento\Integration\Api\CustomerTokenServiceInterface;
 use Magento\TestFramework\Helper\Bootstrap;