[BUGFIX] Fix addQueryStringMethod

Classes/ViewHelpers/Widget/UriViewHelper.php

@@ -130,7 +130,7 @@ class UriViewHelper extends AbstractViewHelper {
 			->setArguments($allArguments)
 			->setSection($arguments['section'])
 			->setAddQueryString(TRUE)
-			->setAddQueryStringMethod($arguments['addQueryStringMethod'])
+			->setAddQueryStringMethod($arguments['addQueryStringMethod'] ?? '')
 			->setArgumentsToBeExcludedFromQueryString([$argumentPrefix, 'cHash'])
 			->setFormat($arguments['format'])
 			->build();