[DBX-88683] update 526 state logger with StatsD

[SamStuckey]

Summary

• This work is behind a feature toggle (flipper): NO
• Update the state logger to also use StatsD gauges. this will unblock the desired state visualization.
• For now we are leaving the logs in place as well for full context, if needed.

Related issue(s)

• Ticket
• Datadog docs

Testing done

• New code is covered by unit tests
• Previously this just wrote logs, but Datadog mapping of a changing payload value is better handled with Gauges

What areas of the site does it impact?

526 state logging

Acceptance criteria

• I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• No error nor warning in the console.
• Events are being sent to the appropriate logging solution (comming soon)
• Documentation has been updated (see above)
• No sensitive information (i.e. PII/credentials/internal URLs/etc.) is captured in logging, hardcoded, or specs
• Feature/bug has a monitor built into Datadog (if applicable)
• If app impacted requires authentication, did you login to a local build and verify all authenticated routes work as expected
• I added a screenshot of the developed feature (n/a)

[tommasina-va]

I realize this was the variable name used before too, but what is dp?

[tommasina-va]

LGTM! I'm curious to look at the gauges on the dashboard. Good find!

[rjohnson2011]

Can you try merging in master to see if that fixes the test failures?