[client] wayland: handle output scale changes

If the scale factor of an wl_output changes while the client is running,
the maximum scale factor is not updated. This may result in incorrect
scaling.

Therefore, when the scale factor is changed, we should generate a
resize event.

client/displayservers/Wayland/wayland.c

@@ -89,6 +89,7 @@ static bool waylandProbe(void)
 static bool waylandInit(const LG_DSInitParams params)
 {
   memset(&wlWm, 0, sizeof(wlWm));
+  wl_list_init(&wlWm.surfaceOutputs);
 
   wlWm.warpSupport = option_get_bool("wayland", "warpSupport");