Summary:
drop the global settings and export the service wich will activate
the appmenu kded

Test Plan:
adding the menu button makes new apps export it,
removing it makes new apps using the interlal one again

Reviewers: #kwin, #plasma, davidedmundson

Reviewed By: #plasma, davidedmundson

Subscribers: ngraham, davidedmundson, broulik, plasma-devel, kwin

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D9216