Crash when using async version of presentCheckoutPreferences()

[cwimberger]

When using the async version of presentCheckoutPreferences() and a reader is selected, the app crashes with
Thread 1: EXC_BAD_ACCESS (code=1, address=0x28)
as soon as the Done button is tapped to close the view controller.

After further investigation, we discovered that the completion block of the older non-async presentCheckoutPreferences() is called multiple times. That might be the issue in the SDK.

As a workaround, we use the following code:

static func presentCheckoutPreferencesFixed(from vc: UIViewController, animated: Bool) async throws -> Bool {
     return try await withCheckedThrowingContinuation { @MainActor cont in
         var resumed = false
         
         self.presentCheckoutPreferences(from: vc, animated: animated) { @MainActor success, err in
             if resumed { return }
             resumed = true
             
             if let err {
                 cont.resume(throwing: err)
             } else {
                 cont.resume(returning: success)
             }
         }
     }
 }

It would be great if you can fix this issue in the SDK.