What does this PR do?

The code for training models via zero shot distillation was breaking because the .map() function was removing the labels field from the dataset object. This PR fixes the issue by changing the way the tokenizer is called via the map() function.

Fixes https://github.com/huggingface/transformers/issues/12182

Before submitting

• [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• [X] Did you read the contributor guideline, Pull Request section?
• [X] Was this discussed/approved via a Github issue or the forum? Please add a link to it if that's the case.
• [ ] Did you make sure to update the documentation with your changes? Here are the documentation guidelines, and here are tips on formatting docstrings.
• [ ] Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. @patil-suraj @VictorSanh

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint.

This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

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