Remove ignored session store config

We set the session store in an initializer and therefore the development
config was overridden without having any effect.

config/environments/development.rb

@@ -22,8 +22,6 @@ Openfoodnetwork::Application.configure do
     }
   end
 
-  config.session_store :cache_store, key: "_sessions_development", compress: true, pool_size: 5, expire_after: 1.year
-
   config.eager_load = false
 
   # Show full error reports and disable caching