Fix failure of installing pyaudio in Online_Offline_Speech_Commands_Demo.ipynb
# What does this PR do ?
When running `tutorials/asr/Online_Offline_Speech_Commands_Demo.ipynb` in Google Colab, it failed to install `pyaudio` and the following step `import pyaudio as pa` break.

![Screenshot 2023-09-08 at 17 11 13](https://github.com/NVIDIA/NeMo/assets/1953397/c3f735db-07eb-4a69-a51e-14b1a9d53b5f)

Removing `sox` from `apt-get install` command would solve this failure. And even if we remove `sox` explicitly in this command, it will be successfully installed through following command `python -m pip install git+https://github.com/NVIDIA/NeMo.git@$BRANCH#egg=nemo_toolkit[asr]`.

# Changelog 
- Fix the failure of install pyaudio

# Before your PR is "Ready for review"
**Pre checks**:
- [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?
- [x] 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**:
- [ ] New Feature
- [x] Bugfix
- [ ] Documentation

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


## Who can review?
@titu1994, @redoctopus, @jbalam-nv
