[BUGFIX] Prevent PHP 8 warning exception due to missing array keys

This prevents an exception for missing array keys when using an
extbase repository in the "render-preProcess" hook.

Resolves: #95674
Releases: master
Change-Id: Ia3ba1232097ec308acadaae4cdd137a39130d4b6
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/71843
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>

typo3/sysext/extbase/Classes/Configuration/FrontendConfigurationManager.php

@@ -155,6 +155,10 @@ protected function overrideStoragePidIfStartingPointIsSet(array $frameworkConfig
      */
     protected function overrideConfigurationFromPlugin(array $frameworkConfiguration): array
     {
+        if (!isset($frameworkConfiguration['extensionName']) || !isset($frameworkConfiguration['pluginName'])) {
+            return $frameworkConfiguration;
+        }
+
         $setup = $this->getTypoScriptSetup();
         $pluginSignature = strtolower($frameworkConfiguration['extensionName'] . '_' . $frameworkConfiguration['pluginName']);
         $pluginConfiguration = $setup['plugin.']['tx_' . $pluginSignature . '.'] ?? null;