fix/sentences containing white spaces for ConllDataset

[Prikshit7766]

Description

It is cause by the logic in load_data and load_raw_data for ConllDataset

sentences = doc.strip().split("\n\n")

so it is not able to handel condtion where sentence are seprated by

\n   \n

we not are doing the splitting of sentences in the right way

change the condtion to

sentences = re.split(r"\n\n|\n\s+\n", doc.strip())

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➤ Fixes #680

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Usage

Checklist:

• I've added Google style docstrings to my code.
• I've used pydantic for typing when/where necessary.
• I have linted my code
• I have added tests to cover my changes.

Screenshots (if appropriate):

[JulesBelveze]

LGTM