[BUGFIX] Minor fixes in SiteLanguage

This patch fixes some minor issues in getter methods.

Resolves: #84670
Releases: master
Change-Id: I4123238ca17bc3c3463090117b975997ea092a7e
Reviewed-on: https://review.typo3.org/56610


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>