Merge branch '33940-cache-flipper_gate-query' into 'master'

Add the Flipper::Middleware::Memoizer middleware

Closes #33940

See merge request !12359

config/initializers/flipper.rb

+require 'flipper/middleware/memoizer'
+
+Rails.application.config.middleware.use Flipper::Middleware::Memoizer,
+  lambda { Feature.flipper }

lib/feature.rb

@@ -39,8 +39,6 @@ class Feature
       get(key).disable
     end
 
-    private
-
     def flipper
       @flipper ||= begin
         adapter = Flipper::Adapters::ActiveRecord.new(