fix an overly broad CSS selector for notifications

Unfortunately it was breaking some useful behaviour in the slide app

customize.dist/src/less2/include/notifications.less

@@ -10,6 +10,9 @@
         max-width: 300px;
         display: flex;
         flex-flow: column;
+        & hr {
+            margin: 0px !important;
+        }
         .cp-notification {
             min-height: @notif-height;
             display: flex;
@@ -40,9 +43,6 @@
             }
         }
     }
-    hr {
-        margin: 0px !important;
-    }
     .cp-notifications-gotoapp {
         p {
             padding: 10px 0 !important;