[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.h

@@ -238,6 +238,7 @@ void waylandRegistryFree(void);
 // window module
 bool waylandWindowInit(const char * title, bool fullscreen, bool maximize, bool borderless);
 void waylandWindowFree(void);
+void waylandWindowUpdateScale(void);
 void waylandSetWindowSize(int x, int y);
 void waylandSetFullscreen(bool fs);
 bool waylandGetFullscreen(void);