wip Adjust to wlroots upstream layer shell changes
See https://github.com/swaywm/sway/commit/d19f4f7bf866660d2199cb726bc3708eb42f98dd
wip until we switch to > 0.8.1 (tested with https://github.com/swaywm/wlroots/commit/b81bb2ef3040e5cf3dcffbddcb5389775c879d85)
Edited by Guido Gunther