Remap speakers to continuous range of speaker_id for dataset AISHELL3
# What does this PR do ?

Remap discrete speakers of AISHELL3 (like SSB0005, SSB0009 etc.) to continuous range of speaker_id (from 1 to 174)

# Changelog 
- Remap speakers to a continuous range of speaker_id for dataset AISHELL3

# Usage
```python
from nemo.collections.tts.models.base import SpectrogramGenerator, Vocoder
from nemo.collections.tts.models import FastPitchModel, HifiGanModel

text = "这些新一代的中央处理器不只效能惊人，价格也十分有竞争力。"
device = "cpu"
fastpitch_model = FastPitchModel.restore_from("~/Downloads/aishell3.nemo").eval().to(device)
model = HifiGanModel.from_pretrained(model_name="tts_zh_hifigan_sfspeech").eval().to(device)

# Normalize the text and convert it into individual phonemes/tokens.
tokens = fastpitch_model.parse(text)

# Generate spectrogram from text
spectrogram = fastpitch_model.generate_spectrogram(tokens=tokens, speaker=1)

# Invert the spectrogram into audio samples
audio = model.convert_spectrogram_to_audio(spec=spectrogram)

# Convert output from pytorch tensor to numpy array
audio = audio.cpu().detach().numpy()

import soundfile as sf

sf.write("sample.wav", audio.T, 22050, format="WAV")
```
Sample with `speaker=1` [001.zip](https://github.com/NVIDIA/NeMo/files/12736697/001.zip)
Sample with `speaker=100` [100.zip](https://github.com/NVIDIA/NeMo/files/12736729/100.zip)

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- [x] Make sure you read and followed [Contributor guidelines](https://github.com/NVIDIA/NeMo/blob/main/CONTRIBUTING.md)
- [ ] Did you write any new necessary tests?
- [ ] Did you add or update any necessary documentation?
- [ ] Does the PR affect components that are optional to install? (Ex: Numba, Pynini, Apex etc)
  - [ ] Reviewer: Does the PR have correct import guards for all optional libraries?
  
**PR Type**:
- [x] New Feature
- [ ] Bugfix
- [ ] Documentation

If you haven't finished some of the above items you can still open "Draft" PR.


## Who can review?
@XuesongYang 

# Additional Information
* https://github.com/NVIDIA/NeMo/pull/7409#discussion_r1336613673
