a11y/managermenu: bugfix navbar z-index #16684

The z-index is too high and prevents extras like ace/tinymce/commerce modal and so on being on top.

Author: jenswittmann

_build/templates/default/sass/_navbar.scss

@@ -27,7 +27,7 @@
   background: $colorSplash;
   max-width: $navbarWidth;
   position: absolute;
-  z-index: 9999;
+  z-index: 2;
   height: 100%;
 }