Frame VAD eval not working?
**Describe the bug**
I prepared a test manifest in the required format (i.e. with rttm label, because it doesn't work with the format indicated in the documentation), and tried to run the inference with the default parameters of the frame vad inference. I changed `evaluate` to `True` and here is my output:
```
[NeMo I 2023-06-28 13:40:46 frame_vad_infer:181] Evaluating VAD results
Evaluating VAD results:   0%|                                                                                                                                                                                                     | 0/1508 [00:00<?, ?it/s][NeMo W 2023-06-28 13:40:46 nemo_logging:349] .../Tools/miniconda3/envs/nemo_official/lib/python3.8/site-packages/pyannote/metrics/utils.py:200: UserWarning: 'uem' was approximated by the union of 'reference' and 'hypothesis' extents.
      warnings.warn(
    
Evaluating VAD results: 100%|█████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 1508/1508 [00:08<00:00, 173.89it/s]
[NeMo I 2023-06-28 13:40:58 frame_vad_infer:192] AUROC: 0.9776
[NeMo I 2023-06-28 13:40:58 frame_vad_infer:193] DetER=100.0000, False Alarm=0.0000, Miss=100.0000
[NeMo I 2023-06-28 13:40:58 frame_vad_infer:194] with params: {'onset': 0.3, 'offset': 0.3, 'pad_onset': 0.2, 'pad_offset': 0.2, 'min_duration_on': 0.2, 'min_duration_off': 0.2, 'filter_speech_first': True}
[NeMo I 2023-06-28 13:40:58 frame_vad_infer:195] Done!
```

When I look at the output in:
```
vad_frame_outputs/seg_output_onset0.3-offset0.3-pad_onset0.2-pad_offset0.2-min_duration_on0.2-min_duration_off0.2-filter_speech_firstTrue-/file_id_1.rttm
```
there is definitely some overlap with the reference segments. So Miss=100 is unlikely. There are also some segments detected which are not in the reference, so False Alarm=0 is unlikely.
Could it be that the evaluation is missing something?

Thanks for your help!
