[FOLLOWUP][TASK] Deprecate methods related to traditional AJAX request dispatching

The ExtDirect API cannot convert the Uri object from a string,
this is fixed now by casting to a string now.

Resolves: #75340
Releases: master
Change-Id: I140e9b4ee9af0b024eb5074d7f602156cf50e4a1
Reviewed-on: https://review.typo3.org/47534


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>

typo3/sysext/core/Classes/ExtDirect/ExtDirectApi.php

@@ -145,7 +145,7 @@ class ExtDirectApi
         } else {
             /** @var UriBuilder $uriBuilder */
             $uriBuilder = GeneralUtility::makeInstance(UriBuilder::class);
-            $url = $uriBuilder->buildUriFromRoute('ajax_ext_direct_route', ['namespace' => $namespace]);
+            $url = (string)$uriBuilder->buildUriFromRoute('ajax_ext_direct_route', ['namespace' => $namespace]);
         }
         return $url;
     }