Fix tags styles in forms

These styles were broken in commit 2614de79c, since there we only
considered scenarios where the `tags` element is a list. In these forms, however, the `tags` element is a regular <div> tag.

app/assets/stylesheets/tags.scss

@@ -1,6 +1,3 @@
-ul {
+.tags {
-
-  &.tags {
   @extend %tags;
 }
-}