[WEB]Issue of saving/not saving payment information for future.

[hexch]

Describe the bug

I'm using the stripe_web package.
It seems unable to opt-out of saving payment information during confirmPayment.
Here is my code:

await WebStripe.instance.confirmPayment(
  model.stripeSecret,
  const PaymentMethodParams.card(
    paymentMethodData: PaymentMethodData(),
  ),
  PaymentMethodOptions(
    setupFutureUsage: saveCardInfo
        ? PaymentIntentsFutureUsage.OffSession
        : null,
  ),
);

I have noticed that the code in stripe_web does not align with the documentation provided by Stripe. I will submit a pull request shortly for your review. Please help confirm.

To Reproduce
Steps to reproduce the behavior:

1. set saveCardInfo to false
2. do confirmPayment
3. check the Payment Information of the Customer in Stripe Dashboard

Expected behavior
If saveCardInfo is set to false, Stripe should not store the user-inputted payment information.

Smartphone / tablet

• Device: Mac
• Package version:flutter_stripe_web 4.4.0

Additional context
none

[hexch]

Thanks for reviewing.