Request to customize origin and size in octree.convert_from_point_cloud()

### 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).

### Proposed new feature or change

Hi, I found that `octree.convert_from_point_cloud()` will adaptively adjust the origin and size of the octree based on the input pointcloud even if they are set when the octree was initialized.

Is it possible for this function to take two extra optional arguments `origin` and `size` so that they can be fixed?

### References

_No response_

### Additional information

_No response_