Bug - not able to unset Stripe account

[vytautas-pranskunas-]

hi @jonasbark Is there a way how to unset Stripe account?
Because now - once 3ds is triggered I am setting Stripe account. But after i need to unset it because otherways all other actions, like payment methods creation, will be made in that account...

I see in this post guy is doing this is setting it null to fight not corrrect authentication before each payment method creation. But in null safety version param is not nullable :(
https://medium.com/flutter-community/build-a-marketplace-in-your-flutter-app-and-accept-payments-using-stripe-and-firebase-72f3f7228625

I really need a way to reset that header otherways all integration just not correct.
Can you help? If needd I can help.
This is ONLY bug left which blocks us from going LIVE

Also i see it is easy fix I can even do PR because i see you are doing all it needs

 @ReactMethod
  public void setStripeAccount(final String stripeAccount) {
    ArgCheck.notEmptyString(mPublicKey);
    mStripeAccountId = stripeAccount;
    if (stripeAccount == null) {
      mStripe = new Stripe(getReactApplicationContext(), mPublicKey);
    } else {
      mStripe = new Stripe(getReactApplicationContext(), mPublicKey, stripeAccount);
    }
  }

the only bad stuff is this:

  static void setStripeAccount(String stripeAccount) {
    _channel.invokeMethod('setStripeAccount', {"stripeAccount": stripeAccount});
  }

String is not nullable :(

[vytautas-pranskunas-]

Here you go: #332
Can you merge it please?

[vytautas-pranskunas-]

@jonasbark would you be able to merge this small PR please?