[TASK] Avoid extending ImageViewHelper

To prepare making all view helpers final as anticipated
with #95298, ext:backend ThumbnailViewhelper must no
longer extend ext:fluid ImageViewHelper.
The patch is a simple transition, we may later have
a look at the ThumbnailViewHelper again, since
probably some of the possible arguments are not
needed for thumbnails.

Resolves: #96362
Related: #95298
Releases: main
Change-Id: Ibf0f3ac108ab1849454769a947061a4604eb9fbf
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72666


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>