Wayland: Fix accidental copy during global remove

We were accidentally mutating a copy during cleanup of the viewporter
and fractional scale manager.

Thank you Aaron Franke for finding this out :D

platform/linuxbsd/wayland/wayland_thread.cpp

@@ -824,7 +824,7 @@ void WaylandThread::_wl_registry_on_global_remove(void *data, struct wl_registry
 
 	if (name == registry->wp_viewporter_name) {
 		for (KeyValue<DisplayServer::WindowID, WindowState> &pair : registry->wayland_thread->windows) {
-			WindowState ws = pair.value;
+			WindowState &ws = pair.value;
 			if (registry->wp_viewporter) {
 				wp_viewporter_destroy(registry->wp_viewporter);
 				registry->wp_viewporter = nullptr;
@@ -862,7 +862,7 @@ void WaylandThread::_wl_registry_on_global_remove(void *data, struct wl_registry
 
 	if (name == registry->wp_fractional_scale_manager_name) {
 		for (KeyValue<DisplayServer::WindowID, WindowState> &pair : registry->wayland_thread->windows) {
-			WindowState ws = pair.value;
+			WindowState &ws = pair.value;
 
 			if (registry->wp_fractional_scale_manager) {
 				wp_fractional_scale_manager_v1_destroy(registry->wp_fractional_scale_manager);