Add sitemap generation for Gitlab.com and gitlab-org namespace

In this commit we remove the feature flag that enables the sitemap
generation for the `gitlab-org` namespace in .com.

config/feature_flags/development/gitlab_org_sitemap.yml

----
-name: gitlab_org_sitemap
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/46661
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/276915
-milestone: '13.6'
-type: development
-group: group::editor
-default_enabled: false

ee/app/controllers/sitemap_controller.rb

@@ -7,7 +7,6 @@ class SitemapController < ApplicationController
 
   def show
     return render_404 unless Gitlab.com?
-    return render_404 unless Feature.enabled?(:gitlab_org_sitemap)
 
     respond_to do |format|
       format.xml do

ee/changelogs/unreleased/276915-fj-enable-globally-sitemap-generation.yml

+---
+title: Add sitemap generation for Gitlab.com and gitlab-org namespace
+merge_request: 56947
+author:
+type: added

ee/spec/controllers/sitemap_controller_spec.rb

@@ -24,24 +24,12 @@ RSpec.describe SitemapController do
       let(:dot_com) { true }
 
       context 'with an authenticated user' do
-        let(:flag_value) { true }
-
         before do
-          stub_feature_flags(gitlab_org_sitemap: flag_value)
-
           allow(Sitemap::CreateService).to receive_message_chain(:new, :execute).and_return(result)
 
           subject
         end
 
-        shared_examples 'gitlab_org_sitemap flag is disabled' do
-          let(:flag_value) { false }
-
-          it 'returns :not_found' do
-            expect(response).to have_gitlab_http_status(:not_found)
-          end
-        end
-
         context 'when the sitemap generation raises an error' do
           let(:result) { ServiceResponse.error(message: 'foo') }
 
@@ -49,8 +37,6 @@ RSpec.describe SitemapController do
             expect(response).to have_gitlab_http_status(:ok)
             expect(response.body).to include('<error>foo</error>')
           end
-
-          it_behaves_like 'gitlab_org_sitemap flag is disabled'
         end
 
         context 'when the sitemap was created suscessfully' do
@@ -60,8 +46,6 @@ RSpec.describe SitemapController do
             expect(response).to have_gitlab_http_status(:ok)
             expect(response.body).to eq('foo')
           end
-
-          it_behaves_like 'gitlab_org_sitemap flag is disabled'
         end
       end
     end