Update docs for assigning path to all_video_file_paths
# What does this PR do?

Updating a few lines in the video classification tasks guide as the way its written it seems like we are not actually iterating over the file paths, but rather the string. 

Fixes # (issue)


## Before submitting
- [x] 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](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      Pull Request section?
- [ ] Was this discussed/approved via a Github issue or the [forum](https://discuss.huggingface.co/)? Please add a link
      to it if that's the case.
- [x] Did you make sure to update the documentation with your changes? Here are the
      [documentation guidelines](https://github.com/huggingface/transformers/tree/main/docs), and
      [here are tips on formatting docstrings](https://github.com/huggingface/transformers/tree/main/docs#writing-source-documentation).
- [ ] 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. Feel free to tag
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The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_22522). All of your documentation changes will be reflected on that endpoint.<|||||>@amyeroberts yes you're right, the dataset is downloaded to the .cache directory and extracted into local directory. I have updated accordingly and tested in colab to confirm that its working 

<img width="1387" alt="Screenshot 2023-04-05 at 16 06 57" src="https://user-images.githubusercontent.com/8465628/230124560-1eef5951-70f3-4b10-b4a8-4d1766bcb531.png">
<|||||>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.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.