ENGCOM-6289: Log InvalidRequestException from FrontController validation failure to debug log #25600

 - Merge Pull Request #25600 from marcusirgens/magento2:add-exception-to-debug-log
 - Merged commits:
   1. 49bf35d
   2. 510310b

Author: magento-engcom-team

lib/internal/Magento/Framework/App/FrontController.php

@@ -1,7 +1,5 @@
 <?php
 /**
- * Front controller responsible for dispatching application requests
- *
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
@@ -17,6 +15,8 @@
 use Magento\Framework\App\Request\Http as HttpRequest;
 
 /**
+ * Front controller responsible for dispatching application requests
+ *
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class FrontController implements FrontControllerInterface
@@ -116,6 +116,8 @@ public function dispatch(RequestInterface $request)
     }
 
     /**
+     * Process (validate and dispatch) the incoming request
+     *
      * @param HttpRequest $request
      * @param ActionInterface $actionInstance
      * @throws NotFoundException
@@ -141,7 +143,8 @@ private function processRequest(
                 //Validation failed - processing validation results.
                 $this->logger->debug(
                     'Request validation failed for action "'
-                    .get_class($actionInstance) .'"'
+                    . get_class($actionInstance) . '"',
+                    ["exception" => $exception]
                 );
                 $result = $exception->getReplaceResult();
                 if ($messages = $exception->getMessages()) {