CI: Run pre-commit gh action on only changed files

- [x] closes #38862
- [ ] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry
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Since pre-commit in comment-bot runs on all files, it's a bit slow. Running it only on diff should speed it up significantly.