Make file template dropdowns consistent

app/assets/stylesheets/pages/editor.scss

@@ -204,6 +204,8 @@
   .gitlab-ci-yml-selector,
   .dockerfile-selector,
   .template-type-selector {
+    @include new-style-dropdown;
+
     display: inline-block;
     vertical-align: top;
     font-family: $regular_font;