[TASK] Remove prophecy in EXT:core SessionManagerTest

Resolves: #98771
Releases: main
Change-Id: I3c22353bc827c3a8d0b81261444e1fd3a1e78271
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76798


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