Downgrade log warning -> info
# What does this PR do?

Downgrades the logged messages about the size parameter being converted from int/tuple -> dict from warning to info. 

## Fixes

Addresses part of the issue raised in #20185 - where many downstream tasks would have multiple warning messages, potentially scaring the users and spamming their logs. 

## 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](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.
- [ ] 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?


The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_20202). All of your documentation changes will be reflected on that endpoint.<|||||>Thank you! 