[TASK] Add integrity check for set and setting labels

Labels for site sets and site settings – as added in #104831 - are
now verified for completenes.

The script checkIntegritySetLabels.php checks for required
and optional labels to ensure labels.xlf and settings.definitions.yaml
are in sync.

Resolves: #104867
Related: #104831
Releases: main
Change-Id: I7c91d9ce1fe79ac3137a06b53010fe36418cc896
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/85931


Reviewed-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Garvin Hicking <gh@faktor-e.de>