[BUGFIX] Check if site language is enabled before redirecting

Only if a site language is enabled, it should be taken into account for
redirecting.
To keep the interface valid, the 1st site language is returned if no
other site language is found.

Resolves: #93920
Releases: master, 10.4
Change-Id: I304c845012d3d76cd230e775030ac08a8d003e6b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68775


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>