[!!!][TASK] Remove config.language_alt and config.language

Due to site handling, the TypoScript properties config.language
and config.language_alt have no effect anymore and can be removed.

This patch removes the last forgotten occurrences.

Resolves: #88459
Releases: master
Change-Id: Ic4793035264cc00fe1e5d22b6b1c7cafdbdc49ed
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60842


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>