Summary:
There's nothing relevant in kdeglobals and loading it can lead to noise
when deleting groups that override a system default.

We still cascade which will allow kiosk keys to work as well as relevant
system defaults.

Import/Export is unchanged as that already uses SimpleConfig which
includes this flag.

I don't know if it will fix the relevant issue in the bug or just
reduce noise.

CCBUG: 402139

Test Plan: Compiled.

Reviewers: #kwin, zzag

Reviewed By: #kwin, zzag

Subscribers: zzag, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D17645