[TASK] Make ImageProcessingService strictly typed

Also switches to constructor property promotion in the process.

Used command:

> ./Build/Scripts/runTests.sh -s phpstanGenerateBaseline

Resolves: #98004
Releases: main
Change-Id: Ic55548afe59654da4ab7fc7ab5a4cfb408ab38d8
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75266


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>