Uses stripe.handleNextAction for payment intents

[chrissrogers]

For some payment methods handle their PaymentIntent.next_action by redirecting the user and then returning them to the checkout.

When this occurs, we shall require the three_d_secure_action_token_id be provided upon return, as follows:

const risk = recurly.Risk();
const threeDSecure = risk.ThreeDSecure({
  actionTokenId: myActionTokenId
});
threeDSecure.on('token', function (token) {
  // handle passing the action result
  // token back to your server

  // token.type => 'three_d_secure_action_result'
  // token.id

  // optionally, you may call threeDSecure.remove() to remove the element
});

threeDSecure.attach(document.querySelector('#my-auth-container'));

This change will handle re-submission of the action token, and determine if the Payment Intent has already been confirmed. If it is confirmed, then an action result token will be generated.