[FOLLOWUP][BUGFIX] Add padding to items in tree

The padding must not be added to .list-tree-group.
Otherwise there is too much padding between the key
and equal sign in the TypoScript Object Browser.

Change-Id: I3e5500f555668c53832637ca6ed41e0fb078618b
Releases: master
Resolves: #68244
Reviewed-on: http://review.typo3.org/42008


Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>