Why o3d.io.read_point_cloud() CAN NOT read intensity info from PCD file?

### Checklist

- [x] I have searched for [similar issues](https://github.com/isl-org/Open3D/issues).
- [x] For Python issues, I have tested with the [latest development wheel](https://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [x] I have checked the [release documentation](https://www.open3d.org/docs/release/) and the [latest documentation](https://www.open3d.org/docs/latest/) (for `main` branch).

### My Question

I use o3d.io.read_point_cloud() to read pcd file with intensity( x y z intensity),But the shape of result is (n, 3)?
there is no any error info when program running to end.