[BUGFIX] Followup to CacheBackend patch

Re-add a missing use statement that vanished during rebase.

Resolves: #59587
Releases: 6.3, 6.2, 6.1
Change-Id: I16ac1b9d5a00c4300202eaef493de43fc988a81d
Reviewed-on: https://review.typo3.org/31520
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters