Fix incorrect `padding` property value pair in `labels.scss` (#1104)

This PR corrects the change to `/_sass/labels.scss` made in 551398f9. This change tried to set the `padding-**top**` property to **two** values rather than set the `padding` property to these values (to represent the vertical and horizontal padding values).

_sass/labels.scss

@@ -3,7 +3,7 @@
 .label,
 .label-blue {
   display: inline-block;
-  padding-top: 0.16em 0.56em;
+  padding: 0.16em 0.56em;
   margin-right: $sp-2;
   margin-left: $sp-2;
   color: $white;