[ResponseOps] Most alerting api integration & functional tests do not work on cloud

[mikecote]

When running the alerting functional and api integration tests on cloud, it doesn't use any configuration changes made within config.ts. This means it doesn't allow to create custom plugins, setup pre-configured connectors, etc.

I'm opening this issue to come up with a plan / fix so we can isolate tests that depend on custom configuration from normal tests. There's some refactoring I'm sure can get a good amount of tests working on cloud now that we have built in alert types and build in action types.

[elasticmachine]

Pinging @elastic/kibana-alerting-services (Team:Alerting Services)

[pmuellr]

Hopefully there's some option available to test our config properties that we've whitelisted. I think that's probably the host whitelisting for actions, and actionType enablement.

It probably makes sense to allow preconfigured actions in the cloud (will need to be whitelisted), but I think only if we have a way to access the action secrets in the keystore. Not sure how that's done today - does Kibana config do that automagically somehow? Cloud does provide access to the elastic keystore - to add new key names / secrets, and see a list of the key names.

[mikecote]

This may be a pre-requisite: #58244.