[TASK] Remove unused properties in $LANG

The properties $charsetArray and $typo3_help_url
inside LanguageService are not needed and are outdated,
thus they can be removed.

Resolves: #72069
Releases: master
Change-Id: Icc6bc48297b361b2797614214176e463d25f683f
Reviewed-on: https://review.typo3.org/45137


Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Michael Oehlhof <typo3@oehlhof.de>
Tested-by: Michael Oehlhof <typo3@oehlhof.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>