[BUGFIX] Cast simulated timestamp to int

`DateTimeImmutable::setTimestamp()` requires the timestamp to be an
integer.

Resolves: #103588
Related: #99627
Related: #98045
Releases: main, 12.4, 11.5
Change-Id: I2dba1b3836063872fa04ea38d58b5bd499a8f7d1
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83742
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Rafał Jania <rr.jania@gmail.com>
Tested-by: Rafał Jania <rr.jania@gmail.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Simon Schaufelberger <simonschaufi+typo3@gmail.com>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Simon Schaufelberger <simonschaufi+typo3@gmail.com>

typo3/sysext/frontend/Classes/Middleware/PreviewSimulator.php

@@ -159,8 +159,8 @@ protected function checkIfPageIsHidden(int $pageId, ServerRequestInterface $requ
      */
     protected function simulateDate(ServerRequestInterface $request): bool
     {
-        $queryTime = $request->getQueryParams()['ADMCMD_simTime'] ?? false;
-        if (!$queryTime) {
+        $queryTime = (int)($request->getQueryParams()['ADMCMD_simTime'] ?? 0);
+        if ($queryTime === 0) {
             return false;
         }