[TASK] Add test cases for handling of l18n_cfg field in pages sitemap

The patch also adds tests for the behavior with
$GLOBALS['TYPO3_CONF_VARS']['FE']['hidePagesIfNotTranslatedByDefault']
enabled.

Resolves: #90109
Releases: master, 9.5
Change-Id: I920f81c80aaa17ca0d6ba815fe2a6e1aa7232ffb
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62880


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Benni Mack <benni@typo3.org>