deprecated use of `model_validator(mode="after")` in `MappableConcept`

[jsstevenson]

.venv/lib/python3.12/site-packages/variation/schemas/normalize_response_schema.py:52
  /Users/jss009/code/metakb/server/.venv/lib/python3.12/site-packages/variation/schemas/normalize_response_schema.py:52: PydanticDeprecatedSince212: Using `@model_validator` with mode='after' on a classmethod is deprecated. Instead, use an instance method. See the documentation at https://docs.pydantic.dev/2.12/concepts/validators/#model-after-validator. Deprecated in Pydantic V2.12 to be removed in V3.0.
    @model_validator(mode="after")

vrs-python/src/ga4gh/core/models.py

Line 229 in b573565

@model_validator(mode="after")