Summary: This patch moves the GHNS button to the bottom-right corner, where it is for nearly all other KCMs.

Test Plan: {F6374491}

Reviewers: #plasma, #vdg, davidedmundson

Reviewed By: #plasma, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Maniphest Tasks: T9954

Differential Revision: https://phabricator.kde.org/D16527