Stop 'remove' button depression when active

Noticed by @quis in
https://github.com/alphagov/notifications-admin/pull/4053#issuecomment-957702649

The 'top' position from the GOVUK Frontend button
styles is overriding our 'top' position.

This adds some extra CSS to repeat the 'top'
position in the :active state.

app/assets/stylesheets/components/area-list.scss

@@ -40,6 +40,11 @@
         color: $light-blue-25;
       }
 
+      // set styles so they don't get overriden by govuk-button styles
+      &:active {
+        top: -2px;
+      }
+
       // The box-shadow that separates the remove link from the list item is hidden in
       // high contrast mode. Remake using a border instead
       // Also sets text colour to match govuk-button