[TASK] Update to PHPStan 1.8.9

This update gets rid of some false positives.

Run commands:

> composer req --dev phpstan/phpstan:^1.8.9
> ./Build/Scripts/runTests.sh -s phpstanGenerateBaseline

Resolves: #98610
Releases: main, 11.5
Change-Id: I65425faaf3c9b0f08bacb6fa56e60b97ca905ed1
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76116


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