fix: tests assertion ignore evaluationId

[zhukaihan]

Fix tests' assertions to only assert evaluationId to be there if expected contains it.

[Copilot]

Pull Request Overview

This PR addresses inconsistencies in test assertions by introducing a custom assertion helper function to handle the non-deterministic evaluationId field in variant metadata during testing.

• Adds assertVariantEquals helper function to ignore the evaluationId field when comparing variants
• Replaces all direct Assert.assertEquals calls for variant comparisons with the new helper function

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