adds feature extra to metadata

Proposed changes

This adds the feature extra to the metadata response. Users can use the feature like this:

options = LiveOptions(
            extra="test:one",
        )

They will see a response like this:

MetadataResponse(type='Metadata', transaction_key='deprecated', request_id='2a23a737-c6bf-4ca6-bd29-0495049015e4', sha256='455ffcc8068f5ca8248e6eb47967109deeb5ad949b60f119960cd81a1bb7d060', created='2024-01-25T20:09:06.990Z', duration=10.754625, channels=1, models=['96a295ec-6336-43d5-b1cb-1e48b5e6d9a4'], model_info={'96a295ec-6336-43d5-b1cb-1e48b5e6d9a4': ModelInfo(name='general', version='2023-02-22.3', arch='base')}, extra="{'test': 'one'}")

I tested these with the prerecorded and live examples.

Types of changes

What types of changes does your code introduce to the community Python SDK? Put an x in the boxes that apply

[ ] Bugfix (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)
[ ] Documentation update or tests (if none of the other choices apply)

Checklist

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[ ] I have read the CONTRIBUTING doc
[ ] I have lint'ed all of my code using repo standards
[ ] I have added tests that prove my fix is effective or that my feature works
[ ] I have added necessary documentation (if appropriate)

deepgram / deepgram-python-sdk