Add subActionsParams to connector definition validate fields.

[ersin-erdal]

Follow-on of: #175018

We are testing connector type config, secrets and params schemas in order to be notified when there is a change on them.

But, as SubActionConnectorTypes doesn't have their params schemas listed in anywhere, couldn't test them.

They are registered during the action execution: e.g. https://github.com/ersin-erdal/kibana/blob/main/x-pack/plugins/stack_connectors/server/connector_types/bedrock/bedrock.ts#L57

We can move them in to connectorType definition schema object and create in a for loop during execution, so we can have a list to check against changes.

[elasticmachine]

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

[cnasikas]

We can move them in to connectorType definition schema object and create in a for loop during execution, so we can have a list to check against changes.

I think moving them to the connector's type definition will reduce the simplicity of the sub-actions framework and make the connector's type definition more complex. The sub-action framework uses the actions framework behind the scenes. The schema of the sub-action connectors is defined and passed to the actions framework here. We could enhance the framework to expose the schema of the parameters of the sub-actions without having to instantiate the class (connector). For example, BedrockConnector.getSubActions(). Then the framework when constructing the schema can iterate through the sub-actions and build the params schema as a union of subactions and subactions parameters. Wdyt?