feat: handle unique org for apikeys

[wilsonjr]

• Selects correct organization for scoped API Keys.
• More informative error message when users have no access to datasets.

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Important

Enhance organization selection for scoped API keys and improve error handling for dataset access in nomic/dataset.py.

• Behavior:
  • _get_current_users_main_organization() in nomic/dataset.py now returns the organization if the user is not the owner.
  • _get_dataset_by_slug_identifier() in nomic/dataset.py raises ValueError on 403 status code.
• Versioning:
  • Bump version in setup.py from 3.1.3 to 3.1.4.

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