Add Alipay future usage support

[porter-stripe]

Summary

Adds Alipay support for future-use PaymentIntents and SetupIntents in PaymentSheet. This includes intent-level and payment-method-option-level setup future usage, along with the Alipay mandate shown when saving payment information. The feature is marked as private preview.

Motivation

Alipay future usage private preview

Testing

• New and updated unit tests
• Live gated Alipay confirmation matrix for PaymentIntent, PI+SFU, PI+PMO-SFU, and SetupIntent
• Recorded network fixture replay

Changelog

See diff

[github-actions]

⚠️ Missing Translations
The following strings have been uploaded to Lokalise but are not yet translated.

By saving your payment information, you allow %@ to charge you for future payments in accordance with their terms.

If it's okay for these strings to be unlocalized in master (e.g. this is for an unshipped feature), add the label ship without translations to acknowledge that there are missing translations. Otherwise, wait until translations are available in Lokalise and re-run this job.

New strings are localized on a weekly basis and are downloaded as part of the release process. For more details on how to localize a string, you can refer to this link.

[github-actions]

⚠️ Public API changes detected:

StripePayments

Public API

+  @objc public var currency: Swift.String?
+  @objc public var paymentMethodOptions: StripePayments.STPConfirmPaymentMethodOptions?
+  @objc public var setupFutureUsage: StripePayments.STPPaymentIntentSetupFutureUsage

If you are adding a new public API consider the following:

• Do these APIs need to be public or can they be protected with @_spi(STP)?
• If these APIs need to be public, assess whether they require an API review.

If you are modifying or removing a public API:

• Does this require a breaking version change?
• Do these changes require API review?

If you confirm these APIs need to be added/updated and have undergone necessary review, add the label modifies public API to this PR to acknowledge the interface change.
Additionally, if you modified or removed an existing API, ensure you update the changelog to reflect the necessary version bump for your changes. Regular public API changes require a MAJOR version bump, and SPI API changes (other than declarations using only @_spi(STP) and/or @_spi(ReactNativeSDK)) require a MINOR or MAJOR version bump.

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[porter-stripe]

matches web: https://livegrep.corp.stripe.com/view/stripe-internal/mint/pay-server/stripe-js-v3/src/checkout/hosted/components/ConfirmPayment/ConfirmTerms/ConfirmModeTerms/__snapshots__/ConfirmSetupTerms.test.tsx.snap#L21