[TASK] Fix possible null pointer exception

AbstractTreeView defines the current "scriptUrl",
to build links in the backend. Since this class
may also be called via CLI, e.g. by EXT:impexp,
missing `instanceof` checks are added to prevent
a null pointer exception.

Resolves: #94947
Related: #93158
Releases: master
Change-Id: I795effd17d42944ae0ab32b1ab10cd632ca7c31e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70689


Tested-by: core-ci <typo3@b13.com>
Tested-by: Alexander Nitsche <typo3@alexandernitsche.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Alexander Nitsche <typo3@alexandernitsche.com>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>

typo3/sysext/backend/Classes/Tree/View/AbstractTreeView.php

@@ -15,6 +15,8 @@
 
 namespace TYPO3\CMS\Backend\Tree\View;
 
+use Psr\Http\Message\ServerRequestInterface;
+use TYPO3\CMS\Backend\Routing\Route;
 use TYPO3\CMS\Backend\Routing\UriBuilder;
 use TYPO3\CMS\Backend\Utility\BackendUtility;
 use TYPO3\CMS\Core\Authentication\BackendUserAuthentication;
@@ -176,9 +178,13 @@ abstract class AbstractTreeView
      */
     protected function determineScriptUrl()
     {
-        $this->thisScript = (string)GeneralUtility::makeInstance(UriBuilder::class)->buildUriFromRoutePath(
-            $GLOBALS['TYPO3_REQUEST']->getAttribute('route')->getPath()
-        );
+        if (($GLOBALS['TYPO3_REQUEST'] ?? null) instanceof ServerRequestInterface
+            && ($route = $GLOBALS['TYPO3_REQUEST']->getAttribute('route')) instanceof Route
+        ) {
+            $this->thisScript = (string)GeneralUtility::makeInstance(UriBuilder::class)->buildUriFromRoutePath(
+                $route->getPath()
+            );
+        }
     }
 
     /**