[TASK] Clean up workspace preview top bar

The preview controller is now not attached to the backend module anymore,
as the Preview functionality ("Split Bar on top") is technically a completely
separate backend preview and completely unrelated to the workspaces
Backend Module.

This change also removes several hacks to generate Backend URLs.

Resolves: #84074
Releases: master
Change-Id: Id0ce7093f6d3ac94c8e4a9cfecd78027d26d45df
Reviewed-on: https://review.typo3.org/55931
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Daniel Gorges <daniel.gorges@b13.de>
Tested-by: Daniel Gorges <daniel.gorges@b13.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>

typo3/sysext/workspaces/Classes/Controller/AjaxController.php

@@ -18,6 +18,7 @@
 use Psr\Http\Message\ServerRequestInterface;
 use TYPO3\CMS\Backend\Utility\BackendUtility;
 use TYPO3\CMS\Core\Http\JsonResponse;
+use TYPO3\CMS\Core\Type\Bitmask\Permission;
 
 /**
  * Implements the AJAX functionality for the various asynchronous calls
@@ -50,7 +51,7 @@ public function switchWorkspaceAction(ServerRequestInterface $request): Response
                 ' AND pages.t3ver_wsid IN (0, ' . $workspaceId . ')'
             );
             if ($page) {
-                if ($this->getBackendUser()->doesUserHaveAccess($page, 1)) {
+                if ($this->getBackendUser()->doesUserHaveAccess($page, Permission::PAGE_SHOW)) {
                     break;
                 }
             } else {