fix(optimization): stop emitting required: true inside field schemas

[akashkokare2910]

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Link to Issue or Description of Change

2. Or, if no issue exists, describe the change:

Problem:

Six fields in optimization/data_types.py and optimization/local_eval_sampler.py are declared as Field(required=True, ...). Pydantic v2 has no required argument on Field. It puts unknown keyword arguments into json_schema_extra and emits PydanticDeprecatedSince20 when these modules are imported. The # type: ignore[call-overload] comments on those lines were hiding the mypy error.

The leftover key ends up inside each property's JSON schema. That is invalid JSON Schema, which requires required to be an array of names on the object:

>>> SamplingResult.model_json_schema()["properties"]["scores"]["required"]
True
>>> jsonschema.Draft202012Validator.check_schema(SamplingResult.model_json_schema())
SchemaError: True is not of type 'array'

Solution:

Remove required=True and the six type: ignore[call-overload] comments. The fields have no default, so Pydantic already treats them as required, and validation behavior does not change. The new tests check both points.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

Added tests/unittests/optimization/data_types_test.py:

• test_json_schema_marks_required_fields_at_object_level: fails on main with 'required': True inside the property, and passes with this change.
• test_fields_without_default_are_required: confirms all six fields still fail validation when missing.

Results:

• pytest tests/unittests: 18452 passed, 87 skipped, 22 xfailed (before rebasing onto current main).
• pytest tests/unittests/optimization tests/unittests/evaluation after rebasing: 1002 passed.
• mypy on both changed source files: no issues.
• pre-commit run on the changed files: all hooks pass.

Manual End-to-End (E2E) Tests:

Not applicable. This change only affects schema generation. To check it by hand, run SamplingResult.model_json_schema() and LocalEvalSamplerConfig.model_json_schema(): there is no required key inside the properties, and the object-level required array lists the fields. Importing both modules no longer emits PydanticDeprecatedSince20.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end. (Not applicable, see above.)
• Any dependent changes have been merged and published in downstream modules.

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