[TASK] Replace prophecy in EXT:form RedirectFinisherTest

Resolves: #98982
Releases: main
Change-Id: I84a57c6d11af8a6e540678749ccbbdc13c6e92bf
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76830


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