message: Update System to correctly set IModelConnection onClose listener
diff: @@ -555,7 +555,7 @@ export class System extends RenderSystem {
  return 0;
  });
  // Make this System a subscriber to the the IModelConnection onClose event
  - IModelConnection.onClose.addListener(() => this.removeIModelMap);
  + IModelConnection.onClose.addListener(this.removeIModelMap.bind(this));
  }
  }
  