Resolve pytest warnings

[MelissaAutumn]

We currently are being hit with a bunch of pydantic warnings per test. These are simply deprecation warnings like:

warning : /Users/melissaautumn/Dev/appointment/backend/.venv/lib/python3.12/site-packages/pydantic/_internal/_config.py:284: PydanticDeprecatedSince20: Support for class-based config is deprecated, use ConfigDict instead. Deprecated in Pydantic V2.0 to be removed in V3.0. See Pydantic V2 Migration Guide at https://errors.pydantic.dev/2.7/migration/
warnings.warn(DEPRECATION_MESSAGE, DeprecationWarning)

And should be fairly easy to resolve. Once fixed, confirm that pytest displays 0 warnings in the summary.