Allows the developer to delete the user pool client.Show details from next link. https://docs.aws.amazon.com/ja_jp/cli/latest/reference/cognito-idp/delete-user-pool-client.html
| aws cognito-idp delete-user-pool-client --user-pool-id "MyUserPoolID" --client-id "MyAppClientID" |
| Configuring a User Pool App Client - Amazon Cognito : http://docs.aws.amazon.com/cognito/latest/developerguide/cognito-user-pools-app-idp-settings.html |