[TASK] Replace prophecy in EXT:core PageRouterTest

Resolves: #98737
Releases: main
Change-Id: I12de96341eae97eafb2fa558e8da2f9cc2e40bb6
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76322


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