Aligned changes to Issuable with EE

app/models/concerns/issuable.rb

@@ -128,10 +128,6 @@ module Issuable
       assignees.count > 1
     end
 
-    def milestone_available?
-      project_id == milestone&.project_id || project.ancestors_upto.compact.include?(milestone&.group)
-    end
-
     private
 
     def milestone_is_valid
@@ -277,6 +273,10 @@ module Issuable
     end
   end
 
+  def milestone_available?
+    project_id == milestone&.project_id || project.ancestors_upto.compact.include?(milestone&.group)
+  end
+
   def assignee_or_author?(user)
     author_id == user.id || assignees.exists?(user.id)
   end