[TASK] Remove left-over clear_all_cache code from TS module controller

The frontend part that issued the GET parameter clear_all_cache=1 was
removed in 2008 with the following commit:
94fb08233d

The handling of this unused parameter is therefore removed.

Releases: master
Resolves: #89257
Change-Id: I4d248d388fb8efdb11df9eb7fd6d976338fa65d1
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61804
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/tstemplate/Classes/Controller/TypoScriptTemplateModuleController.php

@@ -201,13 +201,6 @@ public function mainAction(ServerRequestInterface $request): ResponseInterface
         // Checking for first level external objects
         $this->checkExtObj($changedMenuSettings, $request);
 
-        // Clear the cache if requested
-        if (($request->getParsedBody()['clear_all_cache'] ?? $request->getQueryParams()['clear_all_cache'] ?? false)) {
-            $tce = GeneralUtility::makeInstance(DataHandler::class);
-            $tce->start([], []);
-            $tce->clear_cacheCmd('all');
-        }
-
         // Access check...
         // The page will show only if there is a valid page and if this page may be viewed by the user
         $this->pageinfo = BackendUtility::readPageAccess($this->id, $this->perms_clause);