Support test posts to /fill-out-form

[wioux]

Based on a URL param like testmode=1? This would be useful to client applications that integrate with phantom-dc (for their staging environments, testing, development, etc.) so that you can fully exercise the form and integration without actually messaging congress.

In test mode the endpoint should fail if mandatory fields are omitted or the bio_id is invalid, but otherwise return {status: "success"} without actually running the form steps.

[j-ro]

We implement test mode on the app side, that's our solution for this. But feel free to add if you'd like!