[TASK] Harden \TYPO3\CMS\Extbase\Service\ExtensionService

- Use strict type mode
- Use type hints whereever possible
- Use strict type comparison for in_array

Releases: master
Resolves: #87598
Change-Id: I639fbe1edd291af1a183171d59b0bf42988a0613
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/59593


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Stefan Froemken <froemken@gmail.com>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>