Follow-up from "Payment method component for paid signup flow"

The following discussion from !21640 (merged) should be addressed:

• @pslaughter started a discussion:

  nitpick (non-blocking): It looks like this is already in master, but it's a bit weird to have a components directory inside a components directory. Could we create a follow up issue to move subscriptions/new/components/checkout to subscriptions/checkout 😄