Make sure that installed Wayland dev session is a *full* Wayland session

openSUSE defaults to running everything in XWayland, so you're not actually getting a full wayland session without setting these environment variables. This may be appropriate for a user trying out Wayland (arguable) but for developers who know what they're doing, it's not really appropriate. So let's always set these variables when installing the dev session since they fix this issue when using openSUSE (and potentially any other distros set up in the same way) and have no effect in other distros.

cc @fvogt