1573283 - Add no-op telemetry-tag action

Status: NEW

(Firefox :: Normandy Client, enhancement, P2)

Description

[Michael Cooper [:mythmon]]

Normandy should have an action that sends all the same telemetry as a normal experiment, but doesn't actually make any changes to the browser. Users will enroll and unenroll in these recipes in the same way that they would in preference-experiment or addon-study. They'll follow the same recipe-not-seen semantics, call setExperimentActive and setExperimentInactive, and send enroll and unenroll events.

We've done something like this in the past by making preference-experiment actions that set a preference with no effect on the browser (like test.noop-test.2019-08-12). This has usually been to test filter expressions or new deployment pipelines (like Remote Settings).

This type of action can also be used for health monitoring. Creating new recipes that use this action periodically and comparing their enrollment and unenrollment characteristics can help us monitor the health of the larger Normandy system as a whole.

I propose we use the name telemetry-tag for this action, since that is the most direct way of describing what it does, but I don't feel strongly about that.