[Buckets] Raise when a batch reports failed operations (#4954)
* [Buckets] Raise when a batch reports failed operations
* fix pickling of BucketBatchError
* keep only the main test
* Update src/huggingface_hub/hf_api.py
Co-authored-by: Lucain <lucain@huggingface.co>
* fix missing parenthesis
* use a real test against staging
* keep sending chunks after a failure
* fold batch tests into one
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Co-authored-by: Lucain <lucain@huggingface.co>