[shell] Support autohide panel on wayland
Summary:
This makes use of requests to hide and show autohide panels from
kwayland
BUG: 369386
Depends on D3007
Test Plan:
autohide panel now works, with D3080 in kwin, but windows can
cover panel still needs work
Reviewers: graesslin, Plasma
Reviewed By: graesslin, Plasma
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D3084