Change featured tag updates to add/remove activity (#19409)

* Change featured tag updates to add/remove activity

* Fix to check for the existence of feature tag

* Rename service and worker

* Merge AddHashtagSerializer with AddSerializer

* Undo removal of sidekiq_options

app/models/featured_tag.rb

@@ -30,6 +30,10 @@ class FeaturedTag < ApplicationRecord
 
   LIMIT = 10
 
+  def sign?
+    true
+  end
+
   def name
     tag_id.present? ? tag.name : @name
   end