Open the Affirm modal on the review step when pay and complete is clicked

vmarchuk → made their first commit to this issue’s fork.

vmarchuk → changed the visibility of the branch 3517255-open-the-affirm to hidden.

I had to reroll this to accommodate changes from other merges (attached). When testing, I noticed I'd end up on the payment redirect step (e.g., /checkout/8/payment) instead of the simulated successful return from a redirect to advance my order to the checkout completion page. The payment authorization went through fine and the Payment entity was created, I just didn't end up on checkout complete.