Don't send 'automatic payment' email for subscriptions with non-authenticated payment methods

[BethanOFN]

What is the need/problem?

When an order cycle closes which has attached subscriptions, subscription customers are sent an order confirmation email and an 'automatic payment has been processed' email. For customers with a card on their subscription, this email alerts them that they've been charged automatically. For customers with a non-authenticated payment method (e.g. cash on collection/BACs) on their subscription, this email is confusing as they have not provided an automatic payment method. Customers are therefore getting confused, and producers want to be able to turn off this automatic email.

What type of users does this affect (and how many, if known)?

Shoppers (who receive the email and are confused)
Hub Managers (who have to deal with confused customers)
Producers (who have to deal with confused customers)

Potential solutions that could solve the problem?

• Amend the email logic such that the 'automatic payment has been processed' email is only sent to subscriptions with an authenticated payment method attached. Authenticated payment methods are those with:
  spree_payment_methods.type = Spree::Gateway::StripeSCA
• Changing the email content in transifex was considered, however trying to rewrite it to suit both scenarios (you've been automatically charged/you've not been charged and may or may not need to pay) was too long and confusing

Additional context