possible to edit the default color scheme
Summary:
no reason to not allow editing the default color sheme
with an invalid path, everyting falls back to the default,
keeping the dialog fully functional
Test Plan: edited default color scheme, saved as a new one
Reviewers: Plasma, davidedmundson
Reviewed By: Plasma, davidedmundson
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D5406