fix(alert): add annotation for validator (#4807)

Author: kflournoy-sf

ui/components/alert/base/_index.scss

@@ -61,6 +61,15 @@ $alert-gradient-size-background: 64px 64px;
   }
 }
 
+/**
+ * @summary Initializes notification
+ * @selector .slds-notify
+ * @restrict .slds-notify_container div
+ */
+ .slds-notify {
+  /* Empty annotation for validator */
+}
+
 /**
  * @summary Sets styling for warning alert notification
  * @selector .slds-alert_warning