retrievePaymentIntent
Retrieves a PaymentIntent with a client secret.
If the information required to create a PaymentIntent isn't readily available in your app, you can create the PaymentIntent on your server and use this method to retrieve the PaymentIntent in your app.
See https://stripe.com/docs/terminal/payments#create.
Parameters
clientSecret
The client secret of the PaymentIntent to be retrieved
callback
The callback to be called when retrieval completes