fix(ramps): fixes quote race condition bug with missing payment method

[georgeweiler]

Explanation

When switching the selected ramp token (e.g. ETH → BNB), the controller clears the selected payment method and refetches payment methods for the new token. The UI can still call startQuotePolling() in that window (e.g. from a useEffect that hasn’t re-run with the updated state), so the controller saw no payment method and threw.

FIX:

In startQuotePolling(), if there is no selected payment method, return early instead of throwing. Polling will start once payment methods are loaded and the UI calls again. Region, token, and provider still throw when missing, since they aren’t cleared then refetched on switch.

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Low Risk
Small behavior change limited to quote polling startup error handling; main risk is silently not starting polling if callers don’t retry once a payment method is selected.

Overview
Prevents a quote-polling race when switching tokens/providers by changing startQuotePolling() to return early (instead of throwing) if no payment method is currently selected.

Updates the associated unit test to assert non-throwing behavior, and records the fix in the ramps-controller changelog under Unreleased.

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