Show mandate if being reused

[porter-stripe]

Summary

• For saved payment methods like SEPA that show a mandate, we were not showing them. We need to take into account if the payment method is being re-used as well.
• We need a separate fix for US bank account since the mandate isn't technically a part of the form

Horizontal for reference

After fix

Simulator.Screen.Recording.-.iPhone.15.-.2024-07-02.at.12.05.40.mp4

Motivation

🐛

Testing

• Manual

Changelog

N/A

[yuki-stripe]

What does isReusing mean? Does it mean like, whether or not we have a saved payment method selected? Maybe rename isSavedPaymentMethod?

IMO we should branch based on if it's a saved PM or not. If it's not, trigger the old form-based code. If it is, switch on the payment method type. The "generate form" logic just doesn't hold up for saved PMs.

if isSavedPaymentMethod {
  switch paymentMethodType {
   ... manually build mandates
  }
} else {
  ... original form-generating code
}

[yuki-stripe]

Can we add tests for this, too? We can expand testDisplaysMandateBelowList.

[porter-stripe]

Closing from our Slack convo @yuki-stripe