OrientedBoundingBox renders flat

### 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](http://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [X] I have checked the [release documentation](http://www.open3d.org/docs/release/) and the [latest documentation](http://www.open3d.org/docs/latest/) (for `master` branch).

### Describe the issue

When visualizing an `OrientedBoundingBox` like in the following code snippet, the bbox shows no extent in z-direction.
Printing `bbox.extent` shows that the bbox has indeed the right intent. However, when e.g. printing `bbox.get_box_points()`, the z-coordinate of all points is the same and equals the z-center.

### Steps to reproduce the bug

```python
alpha = detection['heading']
R = np.array([
[math.cos(alpha), -math.sin(alpha), 0],
[math.sin(alpha), math.cos(alpha), 0],
[0, 0, 0]
])
bbox = o3d.geometry.OrientedBoundingBox(
np.array([detection['posX'], detection['posY'], detection['posZ'] ]),
R,
np.array([detection['length'], detection['width'], detection['height']])
)
bbox.color = np.array([1, 0 ,0])
vis.add_geometry(bbox)
```

### Error message

_None_

### Expected behavior

A 3D bbox should be rendered in 3 dimension and not only 2.

### Open3D, Python and System information

```markdown
- Operating system: Ubuntu 20.04
- Python version: Python 3.9
- Open3D version: 0.15.2
- System architecture: x86/x64
- Is this a remote workstation?: no
- How did you install Open3D?: pip
- Compiler version (if built from source): none
```

### Additional information

_No response_