REST 404s return generic "Resource Not found" and drop abort() descriptions

[shiwani42]

Issue

What is the issue?

application/web/web_main.py registers a global 404 handler that always returns the plain string "Resource Not found". Flask abort(404, "…") descriptions never reach the client.

That includes abort(404, "No such Cache") on production/Heroku map_analysis cache miss, and abort(404, "No object matches the given search terms") on empty text_search.

The Gap Analysis UI reads e.response.data.message. For a string body that field is missing, so the page shows axios’s generic “Request failed with status code 404”.

abort(400/401/503) are unaffected (no custom handlers).

Expected Behaviour

A REST abort(404, "No such Cache") should surface that text to API clients, e.g. JSON {"message": "No such Cache"} for /rest/v1/*. Non-API 404s can stay a simple page.

Actual Behaviour

Every 404 body is "Resource Not found".

Steps to reproduce

1. Flask test client, HEROKU=True, cache miss:
   GET /rest/v1/map_analysis?standard=OpenCRE&standard=NIST%20800-53%20v5
2. Status is 404 (existing test already checks this).
3. Body is "Resource Not found", not "No such Cache".

Same wipe: GET /rest/v1/text_search?text=no-such-term → 404 "Resource Not found".

Success criteria

• /rest/v1/* 404 responses include the abort() description (JSON message is enough for the Gap Analysis UI).
• Test asserts Heroku/cache-miss map_analysis body contains No such Cache.
• make lint / make mypy / make test green.