[client] wayland: require wl_compositor v3 instead of v4

The only addition to v4 was `wl_surface_damage_buffer`, which we do not
use.

This change should allow running on more compositors (even though v4 is
already old -- 5 years now).

Ref
3384f69ecf.

client/displayservers/Wayland/window.c

@@ -139,7 +139,7 @@ bool waylandWindowInit(const char * title, bool fullscreen, bool maximize, bool
 
   if (!wlWm.compositor)
   {
-    DEBUG_ERROR("Compositor missing wl_compositor (version 4+), will not proceed");
+    DEBUG_ERROR("Compositor missing wl_compositor (version 3+), will not proceed");
     return false;
   }