fix: add specific payment descriptions logic for payment types

[KenLSM]

Problem

Descriptions sent to Stripe during stripe.paymentIntents.create are not properly retrieved after we've released payment by products and variable payments.

Closes FRM-1286

Solution

Identified that there are three different categories of payments to retrieve the description field from.

Fixed -> payments_field.description // due to legacy reasons, fixed payments uses descriptions instead of name
Variable -> payments_field.name
Products -> selected products

Breaking Changes

• No - this PR is backwards compatible

Before & After Screenshots

Due to the sensitivity of the data in the screenshots, please see comment in ticket.

Tests

Hint: use this url to get the payment item on stripe dashboard quickly https://dashboard.stripe.com/test/connect/accounts/<acct_id>/payments/<pi_id>

Variable Payment Form

• Create a variable payment form, set the name as "tis but a variable", and description as "description"
  • Complete making a payment
  • Ensure that payment summary displays "tis but a variable"
  • Ensure that description on Stripe Payment item is "tis but a variable"

Products Payment Form

• Create a Products payment form, create two products
  • Set first item as "item1", "description1" for name and description, and multiple quantity as "OFF"
  • Set second item as "item2", "description2" for name and description, and multiple quantity of 1 to 99
  • Set payment settings as multiple products
  • Complete making a payment with two selected items, and 2nd item to be quantity 10
  • Ensure that payment summary displays "item1 x 1, item2 x 10"
  • Ensure that description on Stripe Payment item is "item1 x 1, item2 x 10"

[foochifa]

Mostly LGTM! Thanks for the tests too! Just some nits below!