desktop-shell: Properly set the shsurf output to that of the view

The shell_surface is (initially) being assigned the default output and
it case it starts on a different ouput, or is being moved there, it it not be
updated to the correct output of the view.

This will break the stacking order of the views by having a fullscreen
view, which will never be demoted a lower stacking order due to newer
non-fullscreen view which will have the shell_surface output set to the
default one. Doing so will ignore the fullscreen view when determining
which view should should be demoted a lower stacking order.

This is only seen in multiple output configuration.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
3 jobs for order-other-moutputs in 1 minute and 39 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Container Prep
passed #1800395
container_prep

00:00:30

 
  Build
passed #1800396
build-native-meson-default-options

00:01:09

passed #1800397
build-native-meson-no-gl-renderer

00:00:26