Set Realm Override User-Initiated Action Lifespan value via API

I’m trying to set the lifespan specificially for email verification, and see I can do this on the Tokens tab in Realm Settings, by selecting “Email Verification” from the list of options for “Override User-Initiated Action Lifespan” and entering the value.

However, I cannot find out how to do this via the REST API. I can see there is “actionTokenGeneratedByUserLifespan” to set the User-Initiated Action Lifespan, but cannot find anything to do this for specific actions.

Is this possible, or have I missed something in the documentation? Any help much appreciated!