[8074] Remove redirect from education.gov.uk domain (#4995)

* Remove redirect from `education.gov.uk` domain

This is redirected at the infrastructure level now, to `service.gov.uk`.

I've deleted the redirect entirely together with it's feature flag,
rather than just switching off the feature flag.

* Remove spec for deleted redirect

config/routes.rb

@@ -16,13 +16,6 @@
     end
   end
 
-  if Settings.features.redirect_education_domain
-    constraints(->(req) { req.host.end_with?("education.gov.uk") }) do
-      root to: redirect(Settings.base_url), as: :education_domain_root
-      get "/:path", to: redirect("#{Settings.base_url}/%{path}"), as: :education_domain
-    end
-  end
-
   get :ping, controller: :heartbeat
   get :healthcheck, controller: :heartbeat
   get :sha, controller: :heartbeat

config/settings.yml

@@ -80,7 +80,6 @@ features:
   integrate_with_dqt: false
   integrate_with_trs: false
   funding: true
-  redirect_education_domain: true
   hesa_trn_requests: false
   hesa_import:
     test_mode: false

config/settings/test.yml

@@ -13,7 +13,6 @@ features:
     school_direct_salaried: true
     school_direct_tuition_fee: true
     pg_teaching_apprenticeship: true
-  redirect_education_domain: true
 
 environment:
   name: beta