[TASK] Replace prophecy in EXT:core SiteConfigurationTest

Resolves: #98750
Releases: main
Change-Id: I3d57299abd943eca8f2e12a3ad56461e7339c28f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76563


Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>