title: Testflight (Apple) In-App Purchases (IAP) Multiple purchase dialogs
body: <p>I am testing my IAP and followed the process outlined by Medium here (<a href="https://medium.com/flutter-community/in-app-purchases-with-flutter-a-comprehensive-step-by-step-tutorial-b96065d79a21" rel="nofollow noreferrer">https://medium.com/flutter-community/in-app-purchases-with-flutter-a-comprehensive-step-by-step-tutorial-b96065d79a21</a>).</p>
  <p>Everything works fine in Android but on iOS, I get multiple instances of the purchase dialog asking for my password before the process will complete.  I've found a few scattered posts online saying it's related to the 'Sandbox' environment that Testflight uses.</p>
  <p>So, is this really 'normal' for Testflight?  Is there a solution or workaround to solve this?  Also - I added a sandbox tester account in App Store Connect but cannot add this email to the internal testing group for the testflight build, how do i do that?</p>