Returns one reward store by ID. Reads are public, so no producer token is needed. A store in any state can be retrieved, but a deleted store returns 404.

state is draft, published or unpublished. reward_items is the single reward item that products in the store are priced in, and sponsors and attributes are the sponsors and key and value pairs attached to it. publish_url and unpublish_url point to the actions that change its state.