[TASK] Update to PHPStan 1.8.7

This update finds new problems and gets rid of some
false positives.

Run commands:

> composer req --dev phpstan/phpstan:^1.8.7
> ./Build/Scripts/runTests.sh -s phpstanGenerateBaseline

Resolves: #98524
Releases: main, 11.5
Change-Id: Idbb8e62aac0b480eb0590e483968741f2b58916d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75985


Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Stefan Bürk <stefan@buerk.tech>