Enabler: Add a /trial-type/status` endpoint

[blairlearn]

The API should expose a /trial-type/status endpoint to report the health of the trial-type lookup.

The endpoint should

• Call the Elasticsearch health check API for the trial type index.
• If the Elasticsearch status is either green or yellow, return a status 200 and the text "alive".
• Otherwise, return a status 500 and the text "Service not healthy."

ESTIMATE TBD

Resources:

Prerequisites

Sub-Tasks

Notes

[blairlearn]

Combined with #57 to add a single /healthcheck/status endpoint