[BUGFIX] Use proper cache name for ContentFetcher

The newly added ContentFetcher class uses the legacy cache name
"cache_runtime" which was renamed in TYPO3 v10.0 to "runtime".

The change modifies the cache to "runtime".

Resolves: #91188
Releases: master
Change-Id: I3d6f1b61f766120f13c5fee2fac78b50adfb35b0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64313


Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Guido Schmechel <guido.schmechel@brandung.de>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Benni Mack <benni@typo3.org>