Start {slm}
Turns on {slm} ({slm-init}).
If the {es} {security-features} are enabled, you must have the manage_slm
cluster privilege to use this API. For more information, see
[security-privileges].
Starts the {slm-init} plugin if it’s not running. {slm-init} starts automatically when a cluster is formed. Manually starting {slm-init} is only necessary if it has been stopped using the [slm-api-stop].