Merge branch 'sh-disable-flipper-midddlware-tests' into 'master'

Disable Flipper memoizer in tests to avoid transient failures

Closes #34278

See merge request !12656

config/initializers/flipper.rb

 require 'flipper/middleware/memoizer'
 
-Rails.application.config.middleware.use Flipper::Middleware::Memoizer,
+unless Rails.env.test?
+  Rails.application.config.middleware.use Flipper::Middleware::Memoizer,
     lambda { Feature.flipper }
+end