Previews the prorated refund amount for a subscription cancellation.
Reuses RefundService::refund_subscription with preview=true so the same
validation logic runs without executing Stripe refunds or creating DB records.
Use a Bearer token to access this API.
Prorated amount available to refund in cents, based on remaining billing period
Total amount paid on the latest invoice, in cents
Current billing period start
Current billing period end
The payment method ID that would be refunded, if available
Last 4 digits of the card that would be refunded, if available