Sets the default card as the payment source when available.
Payment synchronizer requires a payment to be present
Adjusts logic to retrieve active gateway
Adds missing comma
Merge branch 'features/default_credit_card'

* features/default_credit_card:
  Adds missing comma
  Adjusts logic to retrieve active gateway
  Payment synchronizer requires a payment to be present
  Sets the default card as the payment source when available.