Draft: liblomiri-app-launch: Start Qt Snaps with wayland-egl QPA
Right now we set the QT_QPA_PLATFORM to use ubuntumirclient, the (soon to be) deprecated platform abstraction using the Mirclient protocol, in an /etc/profile.d script.
As long as Lomiri runs in dual-mode (supporting both Mirclient and Wayland) it will prefer ubuntumirclient over wayland-egl.
Thus, to enable more Snaps to work OOTB without hackery, set the environment variable to wayland-egl if the app to launch happens to be a Snap.