[TASK] Refactor functional tests migrated in #77381

This patch refactors the tests migrated from unit tests in #77381.
The tests make now use of the fixture functionality to write a
ResourceStorage to the db and get it via the StorageRepository
instead of creating the object via "new".

Resolves: #77388
Releases: master
Change-Id: I500ef1d6c32ae25f8ca1f7fbc1f198df4c0094c3
Reviewed-on: https://review.typo3.org/49357


Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>