fullscreen-shell: Ensure that fs surface is presented on all outputs
fullscreen-shell: Ensure that fs surface is presented on all outputs

When no outputs are present, and no output resource is given,
a fullscreen surface won't get configured. This code ensures
that surface is properly presented on all outputs that get
connected after a surface has been created, but only if no
output resource was previously given.

Signed-off-by: Armin Krezović <31ec4b88003c779f400d1506dcff569d5faae2fb@gmail.com>
Reviewed-by: Pekka Paalanen <0f6ae7001e34c37b02fb2c1c2573ddf8f442136a@collabora.co.uk>

krezovic/weston,krezovic/weston,sir-murray/weston,sir-murray/weston