[BUGFIX] Avoid PHP 8 warnings in LocalCropScaleMaskHelper

Resolves: #96344
Releases: main, 11.5
Change-Id: I986945e16e0a2adef827fc0532a431be7ab25e03
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72770


Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Benni Mack <benni@typo3.org>