Merge branch 'dblessing-remove-app-settings-redirect' into 'master'

Remove deprecated `/admin/application_settings` redirect

Closes #199427

See merge request gitlab-org/gitlab!30532

changelogs/unreleased/dblessing-remove-app-settings-redirect.yml

+---
+title: Remove deprecated /admin/application_settings redirect
+merge_request: 30532
+author:
+type: removed

config/routes/admin.rb

@@ -116,10 +116,6 @@ namespace :admin do
   end
 
   resource :application_settings, only: :update do
-    # This redirect should be removed with 13.0 release.
-    # https://gitlab.com/gitlab-org/gitlab/issues/199427
-    get '/', to: redirect('admin/application_settings/general'), as: nil
-
     resources :services, only: [:index, :edit, :update]
     resources :integrations, only: [:edit, :update] do
       member do