[TASK] Resolve various PHPStan-related issues

Resolves: #102576
Releases: main
Change-Id: I5c24e0e794c224ed28c1f04a8d93d678460aed7a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82056


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>