Removes an old UI page that's no-longer needed

Removes the page, links to the page, and specs for the page

.haml-lint_todo.yml

@@ -113,7 +113,6 @@ linters:
       - "app/views/help/instance_configuration.html.haml"
       - "app/views/help/instance_configuration/_gitlab_ci.html.haml"
       - "app/views/help/instance_configuration/_gitlab_pages.html.haml"
-      - "app/views/help/ui.html.haml"
       - "app/views/import/bitbucket/status.html.haml"
       - "app/views/import/bitbucket_server/status.html.haml"
       - "app/views/invites/show.html.haml"

changelogs/unreleased/bye-bye-ui.yml

+---
+title: Removes the old UI page
+merge_request: 38277
+author:
+type: other

config/routes/help.rb

 get 'help'                        => 'help#index'
 get 'help/shortcuts'              => 'help#shortcuts'
-get 'help/ui'                     => 'help#ui'
 get 'help/instance_configuration' => 'help#instance_configuration'
 get 'help/*path'                  => 'help#show', as: :help_page

locale/gitlab.pot

@@ -25488,9 +25488,6 @@ msgstr ""
 msgid "U2F only works with HTTPS-enabled websites. Contact your administrator for more details."
 msgstr ""
 
-msgid "UI Development Kit"
-msgstr ""
-
 msgid "URL"
 msgstr ""
 

spec/controllers/help_controller_spec.rb

@@ -159,15 +159,6 @@ RSpec.describe HelpController do
     end
   end
 
-  describe 'GET #ui' do
-    context 'for UI Development Kit' do
-      it 'renders found' do
-        get :ui
-        expect(response).to have_gitlab_http_status(:ok)
-      end
-    end
-  end
-
   def stub_readme(content)
     expect(File).to receive(:read).and_return(content)
   end

spec/routing/routing_spec.rb

@@ -115,7 +115,6 @@ end
 #            help GET /help(.:format)                 help#index
 #       help_page GET /help/*path(.:format)           help#show
 #  help_shortcuts GET /help/shortcuts(.:format)       help#shortcuts
-#         help_ui GET /help/ui(.:format)              help#ui
 RSpec.describe HelpController, "routing" do
   it "to #index" do
     expect(get("/help")).to route_to('help#index')
@@ -131,9 +130,6 @@ RSpec.describe HelpController, "routing" do
     expect(get(path)).to route_to('help#show',
                                   path: 'workflow/protected_branches/protected_branches1',
                                   format: 'png')
-
-    path = '/help/ui'
-    expect(get(path)).to route_to('help#ui')
   end
 end