[Issue] data leakage for `dog-breed-identification` - Add to list of known issues

Our agent [discovered](https://github.com/openai/mle-bench/pull/118#issuecomment-3849995645) that this Kaggle competition was derived from the Stanford Dogs Dataset on its own, see PR #118 

Should `dog-breed-identification` be added to the list of [Known Issues](https://github.com/openai/mle-bench?tab=readme-ov-file#known-issues)?
