Refactor Cache-Control and Vary definitions (#24347)

app/controllers/auth/registrations_controller.rb

@@ -152,6 +152,6 @@ class Auth::RegistrationsController < Devise::RegistrationsController
   end
 
   def set_cache_headers
-    response.headers['Cache-Control'] = 'private, no-store'
+    response.cache_control.replace(private: true, no_store: true)
   end
 end