Promote usage_quotas to a global feature

That page allow to sell additional CI minutes and should available
regardless of the namespace subscription.

ee/app/controllers/groups/usage_quotas_controller.rb

@@ -13,7 +13,7 @@ class Groups::UsageQuotasController < Groups::ApplicationController
   private
 
   def verify_usage_quotas_enabled!
-    render_404 unless @group.feature_available?(:usage_quotas)
+    render_404 unless License.feature_available?(:usage_quotas)
     render_404 if @group.has_parent?
   end
 end

ee/app/models/license.rb

@@ -189,6 +189,7 @@ class License < ApplicationRecord
     object_storage
     repository_size_limit
     custom_project_templates
+    usage_quotas
   ].freeze
 
   validate :valid_license

ee/app/views/groups/ee/_settings_nav.html.haml

@@ -22,7 +22,7 @@
       %span
         Audit Events
 
-- if @group.feature_available?(:usage_quotas)
+- if License.feature_available?(:usage_quotas)
   = nav_link(path: 'usage_quota#index') do
     = link_to group_usage_quotas_path(@group), title: s_('UsageQuota|Usage Quotas') do
       %span

ee/changelogs/unreleased/ac-usage-quotas-global-features.yml

+---
+title: Show Usage Quotas regardless of namespace subscription
+merge_request: 14135
+author:
+type: fixed

ee/spec/features/groups/usage_quotas_spec.rb

@@ -19,6 +19,20 @@ describe 'Groups > Usage Quotas' do
       end
     end
 
+    context 'when checking namespace plan' do
+      before do
+        stub_application_setting_on_object(group, should_check_namespace_plan: true)
+      end
+
+      it 'is linked within the group settings dropdown' do
+        visit edit_group_path(group)
+
+        page.within('.nav-sidebar') do
+          expect(page).to have_link('Usage Quotas')
+        end
+      end
+    end
+
     context 'when usage_quotas is not available' do
       before do
         stub_licensed_features(usage_quotas: false)