feat: element type accuracy grouping (#2594)
This PR allow grouping functionality on `evaluate.py`
To test:
Run `PYTHONPATH=. pytest test_unstructured/metrics/test_evaluate.py` or
call `get_mean_grouping(<doctype or connector>, <dataframe or path to
tsv file>, <export directory>, "element_type")`
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Co-authored-by: ryannikolaidis <1208590+ryannikolaidis@users.noreply.github.com>
Co-authored-by: Klaijan <Klaijan@users.noreply.github.com>
