[TASK] Update to PHPStan 1.9.12

The new version finds some more potential problems.

> composer req --dev phpstan/phpstan:^1.9.12
> ./Build/Scripts/runTests.sh -s phpstanGenerateBaseline

Resolves: #99573
Releases: main, 11.5
Change-Id: Ieee3a5881a854946cb180965e4f182b27ea05aaf
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77420


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