[TASK] Improve a type annotation in ListUtility

Also simplify the code of a caller as detected by static code analysis.

Resolves: #97711
Relates: #97705
Releases: main, 11.5
Change-Id: I1323ffe047cc4954a8c031dbb0218739a7d95571
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74959


Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>