Remove UPI payment method and all associated code

[toluo-stripe]

UPI is no longer supported as a payment method. This removes the enum case, model classes, form factory, VPA validator, intent action handling, polling support, UI assets, localization strings, and all related tests.

Committed-By-Agent: claude

Summary

Motivation

Testing

Changelog

[github-actions]

⚠️ Public API changes detected:

StripePayments

Public API

-    @objc get
-    get
-    get
-    get
-  @objc convenience public init(upi: StripePayments.STPPaymentMethodUPIParams, billingDetails: StripePayments.STPPaymentMethodBillingDetails?, metadata: [Swift.String : Swift.String]?)
-  @objc deinit
-  @objc deinit
-  @objc override dynamic public init()
-  @objc override dynamic public var description: Swift.String {
-  @objc public class func decodedObject(fromAPIResponse response: [Swift.AnyHashable : Any]?) -> Self?
-  @objc public class func propertyNamesToFormFieldNamesMapping() -> [Swift.String : Swift.String]
-  @objc public class func rootObjectName() -> Swift.String?
-  @objc public var additionalAPIParameters: [Swift.AnyHashable : Any]
-  @objc public var allResponseFields: [Swift.AnyHashable : Any] {
-  @objc public var upi: StripePayments.STPPaymentMethodUPI? {
-  @objc public var upi: StripePayments.STPPaymentMethodUPIParams?
-  @objc public var vpa: Swift.String {
-  @objc public var vpa: Swift.String?
-  @objc(paramsWithUPI:billingDetails:metadata:) dynamic public class func paramsWith(upi: StripePayments.STPPaymentMethodUPIParams, billingDetails: StripePayments.STPPaymentMethodBillingDetails?, metadata: [Swift.String : Swift.String]?) -> StripePayments.STPPaymentMethodParams
-  case UPI
-  case upiAwaitNotification
-  }
-  }
-  }
-  }
-@objc @_hasMissingDesignatedInitializers public class STPPaymentMethodUPI : ObjectiveC.NSObject, StripePayments.STPAPIResponseDecodable {
-@objc @_inheritsConvenienceInitializers public class STPPaymentMethodUPIParams : ObjectiveC.NSObject, StripePayments.STPFormEncodable {
-}
-}

StripeConnect

SPI API

-      @_spi(PreviewConnect) case upi

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.