Update Stripe to version '2025-04-30.preview'

[voidzenn]

PR: Stripe API upgrades and Level 2/3 handling (bc-v1.129.0)

Summary

This PR updates our Stripe gateways and documents the changes required to support updated Level 2/Level 3 (L2/L3) reporting.

What changed

• Bumped the Stripe API version used by the legacy Stripe payments gateway from the old baseline (previously 2020-08-27 / 2022-11-15 in parts) to the required preview version 2025-04-30.preview. Stripe notified us that this upgrade is required to continue receiving correct L2/L3 rate handling.

• For StripePaymentIntentsGateway we changed behavior around where L3 data is attached:

  • add_level_two now populates payment_details and amount_details. Newer API behavior expects Level 3/line item fields to be included within amount_details instead of a top-level level3 key.
  • add_level_three in stripe_payment_intents.rb was commented out because the gateway places line items inside amount_details (via add_level_two) rather than sending a separate post[:level3] hash.

Files touched

• lib/active_merchant/billing/gateways/stripe.rb — updated to accept and forward Level 3 keys (line items and transaction-level L3 fields).
• lib/active_merchant/billing/gateways/stripe_payment_intents.rb — clarified that add_level_three is intentionally commented out because add_level_two handles amount_details/L3 placement.

References

Followed this Stripe docs for params structure line_items

• https://docs.stripe.com/payments/payment-line-items?level=l3#sample-request-(level-3/product-3-data)