[DOCS] Clarify xpack.actions.enabledActionTypes (elastic#191772)

docs/settings/alert-action-settings.asciidoc

@@ -141,8 +141,12 @@ A boolean value indicating that a footer with a relevant link should be added to
 `xpack.actions.enabledActionTypes` {ess-icon}::
 A list of action types that are enabled. It defaults to `["*"]`, enabling all types. The names for built-in {kib} action types are prefixed with a `.` and include: `.email`, `.index`, `.jira`, `.opsgenie`, `.pagerduty`, `.resilient`, `.server-log`, `.servicenow`, .`servicenow-itom`, `.servicenow-sir`, `.slack`, `.swimlane`, `.teams`, `.thehive`, `.tines`, `.torq`, `.xmatters`,  `.gen-ai`,  `.bedrock`, `.gemini`,  `.d3security`, and `.webhook`. An empty list `[]` will disable all action types.
 +
+--
 Disabled action types will not appear as an option when creating new connectors, but existing connectors and actions of that type will remain in {kib} and will not function.
 
+IMPORTANT: <<pre-configured-connectors,Preconfigured connectors>> are not affected by this setting.
+--
+
 `xpack.actions.microsoftExchangeUrl`::
 The URL for the Microsoft Azure Active Directory endpoint to use for MS Exchange email authentication. Default: `https://login.microsoftonline.com`.