Prevent unnecessary forks iteration at parent update

app/services/projects/update_service.rb

@@ -13,7 +13,7 @@ module Projects
         end
 
         return false unless visibility_level_allowed?(new_visibility)
-        update_forks_visibility_level(new_visibility)
+        update_forks_visibility_level(new_visibility.to_i)
       end
 
       new_branch = params[:default_branch]
@@ -44,11 +44,13 @@ module Projects
     end
 
     def update_forks_visibility_level(new_level)
+      return unless new_level < project.visibility_level
+
       project.forks.each do |forked_project|
         fork_level = forked_project.visibility_level
 
-        if fork_level > new_level.to_i
-          forked_project.visibility_level = new_level.to_i
+        if fork_level > new_level
+          forked_project.visibility_level = new_level
           forked_project.save!
         end
       end