doppler_icp exception

### 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).

### Describe the issue

open3d.exe example pipelines/doppler_icp_registration get exception.

### Steps to reproduce the bug

```python
run open3d.exe example pipelines/doppler_icp_registration,

get following exception:
ModuleNotFoundError: No module named 'pyquaternion'
```

### Error message

ModuleNotFoundError: No module named 'pyquaternion'

### Expected behavior

_No response_

### Open3D, Python and System information

```markdown
- Operating system: Windows 11 64-bit
- Python version: Python 3.9
- Open3D version: 0.18
- System architecture: x86
- Is this a remote workstation?: no
- How did you install Open3D?: pip
```

### Additional information

_No response_

Start by running the documented `open3d.exe example pipelines/doppler_icp_registration` command and inspect the example's imports and dependency configuration for `pyquaternion`. Confirm the example works in the reported Windows, Python 3.9, Open3D 0.18 environment without the ModuleNotFoundError.

Written by the indexing model from the issue text.