Remove multihead from Plasmashell scripting
Summary:
Plasmashell literally never checks the X screen, but we expose it in
this scripting system.
This patch Hardcodes it to the values you'd have on a normal system.
The existing screenCount is unchanged and will still work.
Test Plan: compiles
Reviewers: Plasma, mart
Reviewed By: Plasma, mart
Subscribers: apol, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D9174