json.dumps and non English characters
**Describe the bug**

NeMo uses the `json.dumps` function to save dictionaries to JSON files. `json.dumps` is problematic when there are non-English characters involved. For example, I work with the Slovenian language and `json.dumps` will printout `\u0161` instead of `č` at all locations. To resolve this you need to use the `ensure_ascii=False` option for `json.dumps`. I saw that at a couple of location NeMo already uses this but at the majority locations it does not.

**Steps/Code to reproduce bug**

Run `examples/asr/asr_chunked_inference/rnnt/speech_to_text_buffered_infer_rnnt.py` or a similar transcription script with a model for a language that has non-English characters and inspect the transcript.

**Expected behavior**

Non-English characters should be printed properly in outputs and not as a unicode number.

**Environment overview (please complete the following information)**

NeMo container 22.01.

**Proposed solution**

Add `ensure_ascii=False` to all `json.dumps` calls in NeMo. If you are interested in this, I can prepare a PR.
