[TASK] Fix superfluous strlen() on constant strings

Releases: 6.2, 6.1, 6.0
Resolves: #53477
Change-Id: I27817df25c126beb216c2b933c82ad9c35b74d80
Reviewed-on: https://review.typo3.org/25244
Reviewed-by: Steffen Ritter
Tested-by: Steffen Ritter