How to use 'registration_fgr_based_on_correspondence' function

### 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).

### My Question

Result of registration is fault, when i use function `registration_fgr_based_on_correspondence` .
dataset:3dMatch
3d descriptor: FCGF
result of function `registration_fgr_based_on_feature_matching` is right.(see below)
i input the correspondece_set of result to `registration_fgr_based_on_correspondence`.
```
result_fm = o3d.pipelines.registration. registration_fgr_based_on_feature_matching(source_pcd, target_pcd, source_fea, target_fea, FGRoption)
result_cor = o3d.pipelines.registration. registration_fgr_based_on_correspondence(source_pcd, target_pcd,result_fm.correspondence_set, FGRoption)
```
function `registration_fgr_based_on_feature_matching` did not return the desired result. (see below)
i try other function `registration_ransac_based_on_correspondence`.
the reslut is right.(see below)

Could you please solve my question.