Remove enableGroupedNav advanced setting (#4362) (#4374)

(cherry picked from commit 6118afd)

Co-authored-by: Joe Peeples <[email protected]>

docs/getting-started/advanced-setting.asciidoc

@@ -100,13 +100,6 @@ determines the threshold above which anomaly scores appear in {elastic-sec}:
 
 * `securitySolution:defaultAnomalyScore`
 
-[discrete]
-== Enable grouped navigation
-
-The `securitySolution:enableGroupedNav` setting enables the grouped navigation menu for {elastic-sec}, which groups related pages and highlights commonly visited areas for a streamlined experience.
-
-By default, the {security-app} uses the legacy navigation menu; turn on `securitySolution:enableGroupedNav` to use the grouped navigation menu.
-
 [discrete]
 == Modify news feed settings