fix: 🐛 Fix bounding box not recalculated on model change

Author: Marco Klein

Source/Visuals/Model3D.cs

@@ -62,6 +62,8 @@ public Node3D Model {
         }
 
         this.AddChild(value);
+        this._size = Vector3.Zero;
+        this._boundingBox = null;
       }
     }