Getting room label with MP3D dataset and HM3D

## Habitat-Sim version
0.3.1
## ❓ Questions and Help
Hi there!
I’m encountering the same issue in Matterport3D scenes: scene.get_regions_for_point(point) always returns an empty list, even when sampling points known to be inside a target region. I verified semantic_scene.load_mp3d_house(...) is enabled.

Could you please share how you eventually solved it?