[BUGFIX] Fix loading of language file in indexed_search

As $GLOBALS['LANG'] doesn't exist in the frontend context,
language (xlf) file has to be loaded through pi_loadLL.

Resolves: #69443
Releases: master
Change-Id: I7668acc3b899fe89e5aaf1a1cdb09dc7a36053e2
Reviewed-on: http://review.typo3.org/42946


Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>