[kcmkwin] Use new icons for virtual desktops, touch screen, and screen edges KCMs

Summary: New icons were added in D18483 and D18490, so this is 5.16 only.

Test Plan: {F6565234, size=full}

Reviewers: #vdg, #plasma, ndavis

Reviewed By: #vdg, ndavis

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D18492