use the new GlobalDrawer header property

Summary:
Depends on D25425

BUG: 389533
FIXED-IN: 5.18

Test Plan: {F7774329}

Reviewers: #discover_software_store, ngraham, apol

Reviewed By: #discover_software_store, ngraham, apol

Subscribers: apol, ngraham, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D25426