Close #921 (Flambe Dependency Fix)

[raissinging]

closes #921

There is a dependency issue in the recently merged flambe dataset as it imports the bigbio schemas from the wrong file. I think this PR should fix that issue by importing the schemas using .bigbiohub instead of from bigbio.utils (a file that is in a different folder and which I think causes the ImportError).

• Name: flambe
• Description: a dataset aimed at procedural knowledge extraction from biomedical texts, particularly focusing on single cell research methodologies described in academic papers.
• Paper: https://proceedings.neurips.cc/paper_files/paper/2023/file/23e3d86c9a19d0caf2ec997e73dfcfbd-Paper-Datasets_and_Benchmarks.pdf
• Data: https://github.com/ylaboratory/flambe

Checkbox

• Confirm that this PR is linked to the dataset issue.
• Create the dataloader script hub/hub_repos/my_dataset/my_dataset.py (please use only lowercase and underscore for dataset naming).
• Provide values for the _CITATION, _DATASETNAME, _DESCRIPTION, _HOMEPAGE, _LICENSE, _URLs, _SUPPORTED_TASKS, _SOURCE_VERSION, and _BIGBIO_VERSION variables.
• Implement _info(), _split_generators() and _generate_examples() in dataloader script.
• Make sure that the BUILDER_CONFIGS class attribute is a list with at least one BigBioConfig for the source schema and one for a bigbio schema.
• Confirm dataloader script works with datasets.load_dataset function.
• Confirm that your dataloader script passes the test suite run with python -m tests.test_bigbio_hub <dataset_name> [--data_dir /path/to/local/data] --test_local.
• If my dataset is local, I have provided an output of the unit-tests in the PR (please copy paste). This is OPTIONAL for public datasets, as we can test these without access to the data files.

[phlobo]

@raissinging Thank you for contributing this dataset! Unrelated to this issue, I noticed that your dataset has NER labels, but does not use the bigbio_kb schema. Do you think it would be possible to convert your IOB tags to character offsets and use the bigbio_kb schema instead?