[BUGFIX] Respect sys_language enable fields

This patch adds a call to BackendUtility::BEenableFields()
in the getSystemLanguages() of the TranslationConfigurationProvider
so that hidden records will not be returned any more.

Releases: master, 6.2
Resolves: #59947
Change-Id: I1c73de4621c7490273ce2966130e53add70b81cd
Reviewed-on: http://review.typo3.org/31173
Reviewed-by: Michael Oehlhof <typo3@oehlhof.de>
Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Benjamin Mack <benni@typo3.org>
Tested-by: Benjamin Mack <benni@typo3.org>