feat(ramps): update payment method delay type to array

[georgeweiler]

Explanation

Changes ramp payment method type from string to array to match API response interface.

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
Type-only change plus test fixture updates; risk is limited to downstream consumers that still expect delay to be a string.

Overview
Updates the RampsService PaymentMethod.delay field to use a minutes range array (number[]) instead of a human-readable string, matching the API response shape.

Updates getPaymentMethods test fixtures accordingly and documents the change in the ramps-controller changelog.

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