[TASK] Replace prophecy in EXT:form SaveToDatabaseFinisherTest

Resolves: #98981
Releases: main
Change-Id: I0e8abe44147c90c88f6221efa59fd384959f31ca
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76829


Tested-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>