Merge pull request #723 from extcode/backport-fix-undefined-array-key-itemsPerPage

[BUGFIX] Fix undefined array key "itemsPerPage"

Author: extcode

Classes/Controller/Backend/Order/OrderController.php

@@ -69,7 +69,7 @@ public function listAction(int $currentPage = 1): ResponseInterface
         $this->moduleTemplate->assign('settings', $this->settings);
         $this->moduleTemplate->assign('searchArguments', $this->searchArguments);
 
-        $itemsPerPage = is_numeric($this->settings['itemsPerPage']) ? (int)$this->settings['itemsPerPage'] : 20;
+        $itemsPerPage = (int)($this->settings['itemsPerPage'] ?? 20);
 
         $orderItems = $this->itemRepository->findAll($this->searchArguments);
         $arrayPaginator = new QueryResultPaginator(