Fix `consumed_samples` which was off by one batch
# What does this PR do ?

It fixes `consumed_samples`, which was off by one batch

**Collection**: nlp

# Changelog 
- Fix `consumed_samples`, which was off by one batch

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**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

# Additional Information

This could be an issue for instance when resuming an experiment and using the number of consumed samples to know where to start from (we would end up re-processing a batch that should have been skipped).