[Alerting] Show a warning when creating an alert if no actions are defined

[Zacqary]

Kibana version: 7.8.0

User should not be able to save an alert if all fields are filled out but no actions are defined. (Maybe add a "required" label to the actions section?)

[elasticmachine]

Pinging @elastic/logs-metrics-ui (Team:logs-metrics-ui)

[Zacqary]

Upon investigation this turns out to be a question for @elastic/kibana-alerting-services. Some alert types may need zero-action alerts, so we need to figure out the UX here for alert types that wouldn't be useful without actions.

[pmuellr]

It wasn't clear from the offline discussion on this, whether this is causing an error in metrics, or not. Eg, does an alert with no actions break something in metrics? Generally speaking, a solution shouldn't have to know whether an alert has any actions set for it or not.

Alerts with no actions has been supported since we started, for various scenarios, but we understand that they could be considered "incomplete", depending on the scenario.

Current thinking is that we could put some kind of warning banner somewhere, indicating no actions have been set on the alert, as a reminder to the user. But I don't believe there are any plans to enforce that alerts must have at least one action.

[mikecote]

It was discussed during today's sync that the best option would be to show a confirmation modal on save when no actions exists.

[Zacqary]

Reassigning this to @elastic/kibana-alerting-services