[BUGFIX] Ensure string is passed to f:sanitize.html view helper

Resolves: #95573
Releases: master, 10.4
Change-Id: I13742f80588d8d1d566d08e7b51c165a5139fe50
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/71538


Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Hader <oliver.hader@typo3.org>

typo3/sysext/fluid/Classes/ViewHelpers/Sanitize/HtmlViewHelper.php

@@ -94,7 +94,7 @@ class HtmlViewHelper extends AbstractViewHelper
     {
         $value = $renderChildrenClosure();
         $build = $arguments['build'] ?? 'default';
-        return static::createSanitizer($build)->sanitize($value);
+        return static::createSanitizer($build)->sanitize((string)$value);
     }
 
     protected static function createSanitizer(string $build): Sanitizer