Issue #2446889: Use element-invisible class

sass/partials/utilities/_mixins.scss

@@ -65,27 +65,9 @@
   }
 }
 
-@mixin element-invisible {
-  position: absolute !important;
-  clip: rect(1px 1px 1px 1px); /* IE6, IE7 */
-  clip: rect(1px, 1px, 1px, 1px);
-  overflow: hidden;
-  height: 1px;
-}
-
-@mixin element-visible {
-  position: inherit !important;
-  clip: inherit;
-  overflow: inherit;
-  height: inherit;
-}
-
 @mixin new-user-badge {
   background-color: #0D7DC1;
   color: white;
   text-align: center;
   text-transform: uppercase;
-  span {
-    @include element-invisible;
-  }
 }