wayland: Don't try to disconnect the listener from the signal handler

This is not needed since the instance is being destroyed and in fact
actively harmful when code called from other handlers disconnects us
for other reasons. In that case we might crash because the
disconnection doesn't prevent other handlers from running in the
current signal emission and thus we try to remove ourselves from an
empty list.
wayland: Remove destroy listener

Do to a bad mixup, the surface listener was never actually fired.
This was accidentally fixed as part of a refactoring in a27fb19,
but the surface listener was broken, and we started crashing. To
fix, just remove the surface listener, as we've mostly been testing
without it.