Update existing clients payment method to CC

Option 1 (probably simplest) (1 week):
Send email notification to STRR online banking accounts notifying of upcoming payment method change and encourage to change to credit card on their own (notebook)
On transition date (notebook)
update payment account to Credit Card
we update corp type payment method data to remove online banking (this removes the ability to select online banking)
keep is_online_banking_allowed corp type flag as TRUE to allow flow through and complete the online banking existing invoices
new invoices will be created using credit card

Start by locating the transition notebook and the existing payment-account and corporation-type payment-method data it updates. Verify how online-banking invoices continue through the transition while new invoices use credit cards. Done means affected accounts are notified, online banking is no longer selectable for new payments, existing invoices still complete, and new invoices use credit cards.

Written by the indexing model from the issue text.