Locally my IDE reports this line as invalid:

scene::Scene scene(renderer.GetSceneContext());

That's because the API is conditionally available, behind IMPELLER_ENABLE_3D:

#if IMPELLER_ENABLE_3D
  std::shared_ptr<scene::SceneContext> GetSceneContext() const;
#endif  // IMPELLER_ENABLE_3D

... I'm not sure how this works today as a result or why it works on CI.