Unable to add email subscriber to build notifications with existing subscriptions

[Jay2113]

Environment information

N/A

Describe the bug

When attempting to add a new email subscriber to build notifications, the UI prevents saving due to validation errors with existing Lambda function ARN subscriptions.

The Lambda function subscription was manually added to the SNS topic created by Amplify.

Reproduction steps

1. Create or start with an existing Amplify app, add email notifications to it
2. Review the SNS topic created in your AWS account
3. Add a Lambda function as a subscriber on the SNS topic
4. Amplify console lists all subscriptions
5. Add a new email subscriber from the Amplify console
6. Save

[Jay2113]

Marking this as a bug. In the interim, we recommend adding email addresses directly through the SNS console as a workaround.