[Security][Serverless] enableVisualizationsInFlyout advanced setting removed from Serverless (#1611)

Contributes to #1464 by
updating the Serverless docs for the `enableVisualizationsInFlyout`
advanced setting.

Preview: [Access the event analyzer and Session View from the event or
alert details flyout
](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/1611/solutions/security/get-started/configure-advanced-settings#visualizations-in-flyout)
- Added a note indicating the setting's availability.

Corresponding 9.1 PR: TBD

Author: nastasha-solomon

solutions/security/get-started/configure-advanced-settings.md

@@ -132,6 +132,10 @@ Including data from cold and frozen [data tiers](/manage-data/lifecycle/data-tie
 
 ## Access the event analyzer and Session View from the event or alert details flyout [visualizations-in-flyout]
 
+::::{note}
+Available in {{stack}} 9.0.0 only.
+::::
+
 The `securitySolution:enableVisualizationsInFlyout` setting allows you to access the event analyzer and Session View in the **Visualize** [tab](/solutions/security/detect-and-alert/view-detection-alert-details.md#expanded-visualizations-view) on the alert or event details flyout.