FIX: Muted tags are respected by TopicTrackingState (#8467)

When the tag is muted and topic contains that tag, we should not mark that message as NEW.

There are 3 possible settings which site admin can set.
remove_muted_tags_from_latest - always
It means that if the topic got at least one muted tag, we should not mark that topic as NEW

remove_muted_tags_from_latest - only muted
Similar to above, however, if at least one tag is not muted, the topic is marked as NEW

remove_muted_tags_from_latest - never
Basically, mute tag setting is ignored and all topics are set as NEW

app/serializers/current_user_serializer.rb

@@ -27,6 +27,7 @@ class CurrentUserSerializer < BasicUserSerializer
              :redirected_to_top,
              :custom_fields,
              :muted_category_ids,
+             :muted_tag_ids,
              :dismissed_banner_key,
              :is_anonymous,
              :reviewable_count,
@@ -169,6 +170,10 @@ class CurrentUserSerializer < BasicUserSerializer
     CategoryUser.lookup(object, :muted).pluck(:category_id)
   end
 
+  def muted_tag_ids
+    TagUser.lookup(object, :muted).pluck(:tag_id)
+  end
+
   def ignored_users
     IgnoredUser.where(user: object.id).joins(:ignored_user).pluck(:username)
   end