The `feature` and `scenario` names are aliases only available in feature
specs and not needed. It's confusing to have different names and we can
easily move feature specs to system specs when using standard names.
This will let us branch by abstraction. All existing calls to
`#outstanding_balance` will go through `OrderBalance` hence, will
check the feature toggle.
Note that by default, `OrderBalance` will end up calling
`#old_outstanding_balance`. As the name states, that's exactly what
`#outstanding_balance` was so far. This means no consumers will see any
change in behavior. We just added on item in the call stack (sort of).
This will happen if user deletes a saved credit card used previously. In this case, the admin payment details page will render empty details and the payment amount
