Completes #77388104 and #77388104

-Emails from free-form carts should display from which store they were purchased.
-as a navigator app, I can send a generic list of properties in key/value format so that cart item information can be stored in the C2 application (send_cart endpoint)

Paired with Rob and Raphy.
I think the last change we made while pairing didn't make it. This line is still commented out. I am pushing up the change.