wayland/layershell: fix bridge destructor use after free on reload

Under some conditions, Qt will recreate the layer surface. The layer
surface destructor tries to destroy the bridge, but doesn't actually
need to because the bridge is a child of the QWindow owning the layer,
meaning not destroying it is actually completely fine.

Author: outfoxxed

src/wayland/wlr_layershell/surface.cpp

@@ -174,7 +174,10 @@ LayerSurface::LayerSurface(LayerShellIntegration* shell, QtWaylandClient::QWayla
 }
 
 LayerSurface::~LayerSurface() {
-	delete this->bridge;
+	if (this->bridge && this->bridge->surface == this) {
+		this->bridge->surface = nullptr;
+	}
+
 	this->destroy();
 }