[shell] Pass the panel visibility mode to KWayland PanelBehavior
Summary:
The visibility mode needs to be passed to KWayland by mapping to the
PanelBehavior. This is required to pass the correct hint to KWin to
adjust the layering, etc.
BUG: 368499
Reviewers: Plasma
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D2789