[BUGFIX] Use proper FAL API for cache busting

Instead of manually resolving the path of
the processed thumbnail image, use FAL
API "getForLocalProcessing". This prevents
wrong paths when using storages with "baseUri"
set.

Resolves: #101968
Related: #82855
Releases: main
Change-Id: I08d4b64c115ca7ecdab8233b36de801e22109e9f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/81099


Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>