typo in diarization class
**Describe the bug**

In [diarization class (ClusteringDiarizer)](https://github.com/NVIDIA/NeMo/blob/main/nemo/collections/asr/models/clustering_diarizer.py#L395), there is `os.path.json()` function, but I think it is actually `os.path.join()`. 

Nemo version: 1.6.2