pointer-constraints: remove protocol

This implementation as it stands is incomplete/buggy and will make
updating to wlr_scene more complex.

It will be reimplemented after updating to wlr_scene is complete.

build.zig

@@ -108,7 +108,6 @@ pub fn build(b: *zbs.Builder) !void {
 
     scanner.generate("xdg_wm_base", 2);
     scanner.generate("zwp_pointer_gestures_v1", 3);
-    scanner.generate("zwp_pointer_constraints_v1", 1);
     scanner.generate("ext_session_lock_manager_v1", 1);
 
     scanner.generate("zriver_control_v1", 1);