idle_inhibit: Assume view is invisible by default

We have historically considered surfaces without a view visible. This
made sense in case of layer surfaces which do not have a view, but it
also allows unmapped surfaces to act as global inhibitors irrespective
of the current view state, which is not the intention fo the protocol.

As we now explicitly handle layer surfaces, assume that views are only
visible if they can be found and their visibility checked.

sway/desktop/idle_inhibit_v1.c

@@ -126,9 +126,9 @@ bool sway_idle_inhibit_v1_is_active(struct sway_idle_inhibitor_v1 *inhibitor) {
 			return wlr_surface->mapped;
 		}
 
-		// If there is no view associated with the inhibitor, assume visible
+		// If there is no view associated with the inhibitor, assume invisible
 		struct sway_view *view = view_from_wlr_surface(wlr_surface);
-		return !view || !view->container || view_is_visible(view);
+		return view && view->container && view_is_visible(view);
 	case INHIBIT_IDLE_FOCUS:;
 		struct sway_seat *seat = NULL;
 		wl_list_for_each(seat, &server.input->seats, link) {