Merge branch 'dropdown-z-index-update' into 'master'

Increase z-index of dropdowns

Closes #36766 and #36866

See merge request !13889

app/assets/stylesheets/framework/dropdowns.scss

@@ -189,7 +189,7 @@
   width: auto;
   top: 100%;
   left: 0;
-  z-index: 9;
+  z-index: 200;
   min-width: 240px;
   max-width: 500px;
   margin-top: 2px;