layer-shell: exclusive-zone not working on corners anchors causes issues
as per documentation: "If the surface is not anchored, anchored to only two perpendicular edges (a corner), anchored to only two parallel edges or anchored to all edges, a positive value will be treated the same as zero."
In Plasma we have panels that can resize themselves based on the contents, and when they don't take 100% of the screen, they can be anchored in the left (growing on the right), center (growing on both sides), right(growing on the left) of the screen.
Regardless of where the panel is shown in the screen, any maximized windows should never go under the panel (we do have a separate setting for that) As things are now, panels aligned on the left or on the right can't be really used on wayland as they can't set exclusive zones due to this protocol limitation
downstream issue: https://bugs.kde.org/show_bug.cgi?id=475700