[BUGFIX] Hide empty settings in user settings

This ensures normal users do not see the "Admin functions" tab.

Releases: #63558
Resolves: 6.2
Change-Id: Ieee76e86ff35d7b8ffd64edbb004075d621e3b27
Reviewed-on: http://review.typo3.org/35026
Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Reviewed-by: Cedric Ziel <cedric@cedric-ziel.com>
Tested-by: Cedric Ziel <cedric@cedric-ziel.com>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>