Simplify logic using new group notification settings method

app/models/notification_recipient.rb

@@ -156,23 +156,11 @@ class NotificationRecipient
   # Returns the notification_setting of the lowest group in hierarchy with non global level
   def closest_non_global_group_notification_settting
     return unless @group
-    return if indexed_group_notification_settings.empty?
 
-    notification_setting = nil
-
-    @group.self_and_ancestors_ids.each do |id|
-      notification_setting = indexed_group_notification_settings[id]
-      break if notification_setting
-    end
-
-    notification_setting
-  end
-
-  def indexed_group_notification_settings
-    strong_memoize(:indexed_group_notification_settings) do
-      @group.notification_settings.where(user_id: user.id)
-        .where.not(level: NotificationSetting.levels[:global])
-        .index_by(&:source_id)
-    end
+    @group
+      .notification_settings(hierarchy_order: :asc)
+      .where(user: user)
+      .where.not(level: NotificationSetting.levels[:global])
+      .first
   end
 end