Refactor Cache-Control and Vary definitions (#24347)

lib/action_controller/conditional_get_extensions.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module ActionController
+  module ConditionalGetExtensions
+    def expires_in(*)
+      # This backports a fix from Rails 7 so that a more private Cache-Control
+      # can be overriden by calling expires_in on a specific controller action
+      response.cache_control.delete(:no_store)
+
+      super
+    end
+  end
+end
+
+ActionController::ConditionalGet.prepend(ActionController::ConditionalGetExtensions)