[TASK] Make type annotations for trait CookieHeaderTrait more specific

This fixes 2 of the 4 PHPStan warnings with Symfony 6.2.

Resolves: #99235
Releases: main
Change-Id: Id36d0eb39fa1211ded6c41e807f75e11ee9f750e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76872


Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>

typo3/sysext/core/Classes/Http/CookieHeaderTrait.php

@@ -21,6 +21,9 @@ use Symfony\Component\HttpFoundation\Cookie;
 
 trait CookieHeaderTrait
 {
+    /**
+     * @return Cookie::SAMESITE_*
+     */
     private function sanitizeSameSiteCookieValue(string $cookieSameSite): string
     {
         if (!in_array($cookieSameSite, [Cookie::SAMESITE_STRICT, Cookie::SAMESITE_LAX, Cookie::SAMESITE_NONE], true)) {