Updated frontend notification filtering and configuration

• Updated:
- frontend notification filtering and configuration

• Added:
- lastReadNotificationId to initial_state
- minWidth20PX for responsive notification icon hiding on xs

• Removed:
- unused code

app/serializers/initial_state_serializer.rb

@@ -37,6 +37,7 @@ class InitialStateSerializer < ActiveModel::Serializer
       store[:group_in_home_feed] = object.current_account.user.setting_group_in_home_feed
       store[:is_staff]           = object.current_account.user.staff?
       store[:unread_count]       = unread_count object.current_account
+      store[:last_read_notification_id] = object.current_account.user.last_read_notification
       store[:monthly_expenses_complete] = Redis.current.get("monthly_funding_amount") || 0
       store[:favourites_count]   = object.current_account.favourites.count.to_s
     end