[Alerting] Remove state variables from action variable menu in UI

[ymao1]

We currently do not pass state variables for recovered alerts but they do show up in the action variable menu dropdown when the Recovered action group is selected. This should be hidden, similar to how context variables are hidden for Recovered action groups.

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)

[pmuellr]

For some reason I thought we were removing the state variables from ALL the action groups, not just recovered. I guess that's the easiest thing to do today, in case users are using state variables today, they might be confused if they didn't see them listed in a future version of Kibana, for non-recovered action groups.

Commenting here after seeing the video in [Alerting] Remove state variables from action variable menu #123702 (but haven't actually reviewed yet - thanks for the video!!!)

[ymao1]

@pmuellr There are some rule types (uptime mostly) that put all of their variables into state. We will have to work with them to move what makes sense to context before removing state entirely from the UI.