[API] Product requests to fake WFO locations return 200 with empty result

[eric-gade]

Description

If you make a request for a specific product with an invalid WFO code, you still get a 200 (successful) result, just with an empty list as the result.

Example.

As a user of the API, I would expect some kind of error code response, maybe even a 404 with an explanation that the given location is invalid.

Acceptance criteria

• Requests to product listings (like the AFD example above) return a 4xx status code for invalid locations, along with an explanation message