fix: evaluation detail type should be optional

[joker23]

This PR will:

• Updates the common client typing so evaluation detail properties are optional (better compat)
• Moved the non-optional evaluation detail type to RN only (to avoid breaking changes)

---

Note

• Shared SDK types: Make reason optional in LDEvaluationDetail and LDEvaluationDetailTyped (src/api/LDEvaluationDetail.ts). Update createSuccessEvaluationDetail to omit reason when undefined (evaluation/evaluationDetail.ts).
• Inspection flow: LDClientImpl now emits flag detail changes without reason for non-reason cases (e.g., deleted/unknown flags), and tests updated to match (removed reason: null expectations).
• React Native override: Add hooks/variation/LDEvaluationDetail.ts defining RN-specific types with reason | null, and re-export them from index.ts to override common types.
• Hook behavior: useTypedVariationDetail normalizes returned details to ensure reason is null when absent across typed variation methods.
• Tests: Adjust inspector tests to reflect optional reason and updated detail shapes.

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[kinyoklion]

I would like to make null not a possibility. How problematic do we think that would be?

Can RN just ?? null it?

[joker23]

That's actually better... I thought it was nullable in the previous sdk (which was why I made it this way)... but apparently not https://github.com/launchdarkly/js-sdk-common/blob/cb9e954d9bf6715021e169c80a6ab9862cafd226/typings.d.ts#L1030 ... I poke around more, but I would also prefer not having null as a possible value.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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