Refer to pinnable visibilities constant from status serializer pinnable? attribute (#35852)

app/serializers/rest/status_serializer.rb

@@ -155,7 +155,7 @@ class REST::StatusSerializer < ActiveModel::Serializer
     current_user? &&
       current_user.account_id == object.account_id &&
       !object.reblog? &&
-      %w(public unlisted private).include?(object.visibility)
+      StatusRelationshipsPresenter::PINNABLE_VISIBILITIES.include?(object.visibility)
   end
 
   def source_requested?