Review if we haven't missed any place where customer balances are used

[RachL]

Description

Balances are also shown on each orders payments tabs (admin side). Do we need to refactor that bit as well?

Also:

we'll need to review b9d72ce and its PR: #1468. Looks like we stopped using that file? 🔥 🔥 🔥

Acceptance Criteria & Tests

[sauloperez]

Places I found we use oustanding_balance and need to be feature-toggled:

• shared/_payment.html.haml (used by most of the files below)
• Spree::Payment::Processing#calculate_refund_amount
• Api::Admin::OrderSerializer#display_outstanding_balance
• spree/admin/payments/_form.html.haml
• spree/admin/payments/index.html.haml
• spree/admin/payments/new.html.haml
• app/mailers/subscription_mailer.rb
• app/mailers/spree/order_mailer.rb
• lib/open_food_network/payments_report.rb
• engines/order_management/app/services/order_management/order/updater.rb

[mkllnk]

@sauloperez This issue is in Code Review. Is there anything you would like us to look at, double-check?

[sauloperez]

I'd appreciate it if you could thoroughly check the tests on that open PR.

I updated the list of occurrences above for the records. I believe I didn't forget any file.

Re the Payments report, @RachL and I thought it'd be best if we could fix it separately as we did with the bulk coop report so we don't make that PR too broad. It's also the report itself that is broken (it doesn't consider canceled orders) and not the balance calculation. This, however, will lead to inconsistent balances in UK and FR; the report will show a different amount compared to all other pages. We think it's an affordable trade-off given it's not a wildly used report (we still need to confirm this hypothesis with Matomo's data).