Add networkBusinessProfile to seller payment methods

[floriansuess-stripe]

Summary and motivation

APIREVIEW-4954.

iOS SDK counterpart to the Stripe.js change in mint#2041413.

Exposes the API surface for agents to pass a seller's Business Network profile to Payment Element on iOS, enabling PE to display the seller's configured payment methods. Beta header payment_element_seller_payment_methods_beta_1 is automatically included when networkBusinessProfile is provided.

The /v1/elements/sessions request already supports:

GET /v1/elements/sessions

<<< REQUEST <<<
{
   seller_details?: {
      network_id?: string,                // was required
      external_id?: string,               // was required
      business_name?: string,             // was required (local-only, now also sent to API)
      network_business_profile?: string,  // new
   },
}

In the iOS SDK:

@_spi(SharedPaymentToken) public struct SellerDetails {
    public let networkId: String?              // was required
    public let externalId: String?             // was required
    public let businessName: String?           // was required
    public let networkBusinessProfile: String? // new
}

For backwards compatibility, the existing 3-arg initializer SellerDetails(networkId:externalId:businessName:) with non-optional String types is preserved. A new initializer with all-optional parameters enables flexible usage including the new networkBusinessProfile field.

The new network_business_profile field allows agents to specify a BizNet profile ID, from which Stripe resolves the seller's default PMC (provided payment_element_seller_payment_methods_beta_1 is present).

All fields made optional. networkBusinessProfile added. paymentMethodConfigurationId and sellerDetails are now validated as mutually exclusive, passing both returns a PaymentSheetError client-side.

All this together looks like:

// 1. Agent creates intent configuration with seller's BizNet profile
@_spi(SharedPaymentToken) import StripePaymentSheet

let intentConfig = PaymentSheet.IntentConfiguration(
    sharedPaymentTokenSessionWithMode: .payment(amount: 1000, currency: "usd"),
    sellerDetails: .init(
        networkBusinessProfile: "bnp_abc123"  // the seller's profile
    ),
    preparePaymentMethodHandler: { paymentMethod, shippingAddress in
        // handle payment
    }
)

// 2. Payment Element renders the SELLER's payment methods
// The SDK automatically includes the beta header in the elements/sessions request

Note: what we do not do in this PR is act on it, i.e., take that network_business_profile value, resolve it to a seller's PMC, and return the right payment methods in the session response. That will come later.

[github-actions]

⚠️ Public API changes detected:

StripePaymentSheet

Public API

+  case paymentMethodConfigurationAndSellerDetailsMutuallyExclusive

SPI API

-      @_spi(SharedPaymentToken) public init(networkId: Swift.String, externalId: Swift.String, businessName: Swift.String)
-      @_spi(SharedPaymentToken) public let businessName: Swift.String
-      @_spi(SharedPaymentToken) public let externalId: Swift.String
-      @_spi(SharedPaymentToken) public let networkId: Swift.String
+      @_spi(SharedPaymentToken) public init(networkId: Swift.String? = nil, externalId: Swift.String? = nil, businessName: Swift.String? = nil, networkBusinessProfile: Swift.String? = nil)
+      @_spi(SharedPaymentToken) public let businessName: Swift.String?
+      @_spi(SharedPaymentToken) public let externalId: Swift.String?
+      @_spi(SharedPaymentToken) public let networkBusinessProfile: Swift.String?
+      @_spi(SharedPaymentToken) public let networkId: Swift.String?

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 @_spi(STP)-only declarations) require a MINOR or MAJOR version bump.

ℹ️ If this comment appears to be left in error, make sure your branch is up-to-date with master.

[paulcarey-stripe]

Looks good from LPMs.

[toluo-stripe]

I think we can delete this because the new constructor has a default value for networkBusinessProfile

[floriansuess-stripe]

Thanks @tulio-stripe, have addressed.

[tulio-stripe]

Thanks for updating it 🤣

[toluo-stripe]

LGTM, but I'm not an iOS codeowner. There's also an api change that may be a blocker. @wooj-stripe @yuki-stripe can you take a look?