enable GenericModel duck-typed serialization

[tmchartrand]

See https://docs.pydantic.dev/latest/concepts/serialization/#serializing-with-duck-typing

Fields of type GenericModel should be able to be initialized with an instance of a subclass model and have all fields serialized. Currently the model must be dumped before initialization:

aind-data-schema/tests/test_aind_generic.py

Line 61 in b3cc37a

contains_model=Bar(bar="baz", foo=2).model_dump(),

There's currently a note in GenericModel about this and using extra="allow" in the meantime, which doesn't fully solve the problem.

It seems we could either:

• replace uses of GenericModel as a field type annotation with GenericModelType=SerializeAsAny[GenericModel]
• override GenericModel.model_dump_json to have serialize_as_any=True by default

slightly different behavior, don't think I have a preference.

[dbirman]

SerializeAsAny seems to be the preferred option here. Models will automatically serialize and then de-serialize to GenericModel with the original fields included.

[tmchartrand]

@dyf can you take a look at this?

[dyf]

Agree with @dbirman, I like SerializeAsAny.