BUG: 383287
Desktop files such as kde/foo.desktop are identified as kde-foo.desktop
because of the menu spec
```
If the directory contains sub-directories then these sub-directories should be (recursively) scanned as well. The name of the subdirectory should be added as prefix to the desktop-file id together with a dash character ("-")
```
the runner therefore broadly assumed that kde-foo.desktop is always
the desktop file kde/foo.desktop and since kde/ was only used up to KDE3
this assumption formed the basis for sepcial KDE3 compat handling. that is
of course wrong because a service might just as well actually have a
prefix and be actually called kde-foo.desktop rather than
kde/foo.desktop. Specific example: kde-gtk-config.desktop
seeing as this is ancient compatibility code that is actually wrong,
the easiest solution seems to be dropping the code entirely (and thus no
longer assume kde- has some special meaning).
(also I didn't find a way to get the underlying filename of a kservice,
so making the code not wrong seems non-trivial)
CHANGELOG: the GTK settings module now correctly appears in krunner and kickoff