[BUGFIX] Avoid postgresql error previewing a fe_group-protected page

Avoid a postgresql error when previewing a page from the backend which
has an access protection by a fe_group due to PreviewSimulator faking
a fe_user with uid PHP_INT_MAX and sql failure to update the is_online
status of this fake user in PostgreSQL as column fe_users.uid is of type
integer and thus has max value of 2147483647 instead of PHP_INT_MAX.

Releases: main, 11.5, 10.4
Resolves: #97564
Change-Id: I16c866c368a9b3f5ac6bdfacf2c6660a7046df5a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74471


Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>

typo3/sysext/frontend/Classes/Authentication/FrontendUserAuthentication.php

@@ -533,7 +533,9 @@ class FrontendUserAuthentication extends AbstractUserAuthentication
      */
     public function updateOnlineTimestamp()
     {
-        if (!is_array($this->user) || !($this->user['uid'] ?? 0)
+        if (!is_array($this->user)
+            || !($this->user['uid'] ?? 0)
+            || $this->user['uid'] === PHP_INT_MAX // Simulated preview user (flagged with PHP_INT_MAX uid)
             || ($this->user['is_online'] ?? 0) >= $GLOBALS['EXEC_TIME'] - 60) {
             return;
         }