[TASK] Use the proper interface with willReturnCallback in EXT:core tests

- use parameter and return type declarations
- use the same parameter names as in the mocked method
- drop useless `self::anything()` calls
- drop `self::isType()` calls that duplicate the native type declarations

This improves code readability and type safety in the tests.

Resolves: #100314
Releases: main
Change-Id: Icc572eb327b09b05f8637a7d91eb7bc7188344be
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78269


Tested-by: core-ci <typo3@b13.com>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: Nikita Hovratov <nikita.h@live.de>