Default to wayland backend when available for emacs-30

I can't reproduce either of the aforementioned issues anymore with emacs 30 and
the current pgtk build etc so making this the default.

Signed-off-by: Alex Murray <murray.alex@gmail.com>

emacs

@@ -10,11 +10,6 @@
 # toolkit to use by checking if the XDG_SESSION_TYPE environment variable is
 # set to wayland or x11.
 
-# FIXME - remove the following once the various issues like
-# https://github.com/alexmurray/emacs-snap/issues/78 and
-# https://github.com/alexmurray/emacs-snap/issues/79 are resolved
-: "${EMACS_TOOLKIT:=gtk}"
-
 if [ -n "${XDG_SESSION_TYPE}" ]; then
   if [ "${XDG_SESSION_TYPE}" = "wayland" ]; then
     : "${EMACS_TOOLKIT:=wayland}"