Call proper method to replace double underscores with single underscores
Can you please review and approve as soon as possible, the branch becomes out of sync every 2 hours and the whole workflow checks run again when I sync the branch to the main.

@titu1994, @redoctopus, @jbalam-nv, @okuchaiev Just a note, it's fine to not sync with main branch until it says there are merge conflicts.
# What does this PR do ?
The code snippet calling `repalce` instead of `replace` which could raise an `AttributeError`. Updated the code with proper function name

PR for 
https://github.com/NVIDIA/NeMo/issues/8488

**Collection**: automatic speech recognition(ASR)

# Changelog 
- Use proper method to replace double under scores with single underscore during data preperation

# Usage
* N/A for this PR

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# 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?
- [ ] 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

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