[BUGFIX] Sanitize calling htmlspecialchars(...) in SelectViewHelper

htmlspecialchars(...) expects that first argument is a string,
otherwise triggering E_DEPRECATED.

This patch adds a string cast to ensure value is passed as string
to htmlspecialchars(...) in SelectViewHelper.

Resolves: #95830
Releases: master
Change-Id: I0b77234ad6c87f19e7f1f5a45fe16c8fea443530
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72012
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>

typo3/sysext/fluid/Classes/ViewHelpers/Form/SelectViewHelper.php

@@ -351,11 +351,11 @@ protected function getOptionValueScalar($valueElement)
      */
     protected function renderOptionTag($value, $label, $isSelected)
     {
-        $output = '<option value="' . htmlspecialchars($value) . '"';
+        $output = '<option value="' . htmlspecialchars((string)$value) . '"';
         if ($isSelected) {
             $output .= ' selected="selected"';
         }
-        $output .= '>' . htmlspecialchars($label) . '</option>';
+        $output .= '>' . htmlspecialchars((string)$label) . '</option>';
         return $output;
     }
 }