Update capturePayment(), voidPayment(), refundPayment() methods to use PaymentIntent ID

In the capturePayment(), voidPayment(), refundPayment() methods we have the following code:

      $remote_id = $payment->getRemoteId();
      $intent = NULL;
      if (strpos($remote_id, "pi_") === 0) {
        $intent = PaymentIntent::retrieve($remote_id);
        $intent_id = $intent->id;
      }
      else {
        $charge = Charge::retrieve($remote_id);
        $intent_id = $charge->payment_intent;
      }

It should be updated to use only the PaymentIntent ID as we always save it for the payment remoteId.