[TASK] Force integer for specific fields of site configuration

If the site config is saved through the site module the following fields
are saved as integer instead of a string:

- `languageId` of a language item
- `errorCode of an errorHandling item

This change makes it easier to lint the yaml configuration.

Resolves: #92510
Releases: master, 10.4
Change-Id: I3086a6c71a191ac1cbc0c14deadce3fa7fab5f5d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/66046
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/backend/Classes/Controller/SiteConfigurationController.php

@@ -506,6 +506,7 @@ protected function validateFullStructure(array $newSysSiteData): array
                 }
                 if (!in_array((int)$child['errorCode'], $uniqueCriteria, true)) {
                     $uniqueCriteria[] = (int)$child['errorCode'];
+                    $child['errorCode'] = (int)$child['errorCode'];
                     $validChildren[] = $child;
                 } else {
                     $message = sprintf(
@@ -537,6 +538,7 @@ protected function validateFullStructure(array $newSysSiteData): array
             }
             if (!in_array((int)$child['languageId'], $uniqueCriteria, true)) {
                 $uniqueCriteria[] = (int)$child['languageId'];
+                $child['languageId'] = (int)$child['languageId'];
                 $validChildren[] = $child;
             } else {
                 $message = sprintf(