Fix search results covered by dashboard filters (#23920)

frontend/src/metabase/nav/components/AppBar/AppBar.styled.tsx

@@ -2,7 +2,7 @@ import styled from "@emotion/styled";
 
 export const AppBarRoot = styled.header`
   position: relative;
-  z-index: 4;
+  z-index: 5;
 
   @media print {
     display: none;