Fix for top margin for search sort (fix #1692)

* Fix for top margin for search sort

* Left-right margins need to be double the usual margins

src/amo/components/SearchSort/SearchSort.scss

@@ -13,7 +13,7 @@
   background: $base-color;
   border-radius: $border-radius-default;
   border: 0;
-  margin: 0 ($padding-page * 2) $padding-page;
+  margin: $padding-page ($padding-page * 2);
   overflow: hidden;
 }