Removes `testenv` annotations and related code. These annotations originally let you skip x-pack snippet tests in the docs. However, that's no longer possible.
Relates to #79309, #31619
The get SLM status API will only return one of three statuses: `RUNNING`, `STOPPING`, or `STOPPED`.
This corrects the docs to remove the `STARTED` status and document the `RUNNING` status.
Co-authored-by: James Rodewig <40268737+jrodewig@users.noreply.github.com>