[Data Explorer][Discover 2.0] Allow Top Nav to update based on index …

…pattern change (#4889)

Issue Resolve
#4888

Signed-off-by: ananzh <ananzh@amazon.com>

src/plugins/discover/public/application/view_components/canvas/top_nav.tsx

@@ -95,7 +95,7 @@ export const TopNav = ({ opts }: TopNavProps) => {
       showSaveQuery
       useDefaultBehaviors
       setMenuMountPoint={opts.setHeaderActionMenu}
-      indexPatterns={indexPatterns}
+      indexPatterns={indexPattern ? [indexPattern] : indexPatterns}
     />
   );
 };