test(kyc): KycFinancialDataCubit + LoadedSuccess helpers (+17 tests)

[TaprootFreak]

Summary

Stage 43 of the coverage push. Cubit-level coverage of the KYC financial-data step: question loading, conditional visibility, answer routing, navigation, submission and the `LoadedSuccess` view-model helpers.

Cases

Target	Cases
initial state	1 — `KycFinancialDataInitial`
`loadQuestions`	3 — Loading → LoadedSuccess; conditional questions filtered when their condition is unmet; Loading → Failure on service error
`answerQuestion`	2 — no-op outside LoadedSuccess; stores the answer and re-runs the visibility filter (conditional questions appear once their predicate matches)
`submitAndNext`	4 — non-last increments `currentIndex`; last emits Submitting → SubmitSuccess and calls `setFinancialData`; submit error surfaces a Failure; no-op outside LoadedSuccess
`goBack`	3 — decrements `currentIndex` from 1; no emit at index 0; no-op outside LoadedSuccess
`KycFinancialDataLoadedSuccess` helpers	4 — `currentQuestion` at index; `isFirstQuestion` / `isLastQuestion`; `currentResponse` + `hasAnswer` reflect the responses map; `hasAnswer` is false on an empty string response

What's pinned

• Conditional-question visibility is dynamic: `answerQuestion` re-runs the filter so a previously hidden question becomes visible the moment its condition is satisfied. Pinned by a live-flip test on `q3` (visible only when `q1 == 'a'`).
• `submitAndNext` only calls `setFinancialData` once the user is on the last visible question — the non-last branch must never reach the service.
• `goBack` at index 0 must not emit (same state instance pinned with `same`), so the UI doesn't show a spurious rebuild when the user taps Back too hard.
• `hasAnswer` treats an empty string as no answer — pins the contract used by the "Next" button's disabled state.

Test plan

• `flutter test test/screens/kyc/steps/financial_data/kyc_financial_data_cubit_test.dart` — 17 pass
• `flutter analyze` clean on the new file
• CI green