add alarms in the :service_unavaliable return response

[sentry]

This was from slack discussion: https://omgnetworkhq.slack.com/archives/CVCAR51UY/p1596734766005500?thread_ts=1596733773.001600&cid=CVCAR51UY

It seems like the consensus was to add alarm in response?

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Sentry Issue: WEBWALLET-11

Error: The server is not ready to handle the request. Check the alarms for more info.
  at new Promise (<anonymous>)
...
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