[TASK] Change Dropdown rendering for translations

Getting rid of x-classing is the goal and with v12 an event is provided
manipulating the header of the RecordListController.

In favour of using this event instead of x-classing the original class, an event
listener is added generating the dropdown and adding top-most of the recordlist.

This has effects on positioning of the translation dropdown, which now is
rendered before the core dropdown instead of next to it.

Configuration/Services.yaml

@@ -46,6 +46,7 @@ services:
     tags:
       - name: 'event.listener'
         identifier: 'deepltranslate-core/render-translated-flag-in-frontend-preview-mode'
+        event: TYPO3\CMS\Frontend\Event\AfterCacheableContentIsGeneratedEvent
 
   WebVision\Deepltranslate\Core\Event\Listener\UsageToolBarEventListener:
     tags: