Add a nav-mesh pathfinding behavior for 2D and 3D

Extensions/3D/Base3DBehavior.ts

@@ -186,20 +186,6 @@ namespace gdjs {
     content: Object3DDataContent;
   }
 
-  /** @category Objects > 3D Objects */
-  export namespace Base3DHandler {
-    export const is3D = (
-      object: gdjs.RuntimeObject
-    ): object is gdjs.RuntimeObject &
-      gdjs.Base3DHandler &
-      gdjs.Resizable &
-      gdjs.Scalable &
-      gdjs.Flippable => {
-      //@ts-ignore We are checking if the methods are present.
-      return object.getZ && object.setZ;
-    };
-  }
-
   /**
    * A behavior that forwards the Base3D interface to its object.
    * @category Core Engine > Behavior