[TASK] Replace prophecy in EXT:form ConfigurationServiceTest

Resolves: #98979
Releases: main
Change-Id: I4c3d342b783a516661da33bdc04834967a91302b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76823


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