[BUGFIX] Prevent "undefined variable $isSavingOfMailAllowed in ... Fo…

…rmController"

One of our clients is using TYPO3 11 with powermail 10.8.1 (latest for this TYPO3 version so far). A form is set with activated double opt in. When the user clicks on the link in the mail to confirm the message, an exception is thrown.

Related: https://projekte.in2code.de/issues/64878

Classes/Controller/FormController.php

@@ -194,6 +194,7 @@ public function initializeCreateAction(): void
      */
     public function createAction(Mail $mail, string $hash = ''): ResponseInterface
     {
+        $isSavingOfMailAllowed = false;
         $this->signalDispatch(__CLASS__, __FUNCTION__ . 'BeforeRenderView', [$mail, $hash, $this]);
         /** @noinspection PhpUnhandledExceptionInspection */
         $this->dataProcessorRunner->callDataProcessors(