Only grant access to Admin Audit Log when feature available

Only when the license allows Admin Audit Log, show the Audit Log
button on the Admin page and make it possible to visit that
page (return 404 otherwise).

app/controllers/admin/audit_logs_controller.rb

 class Admin::AuditLogsController < Admin::ApplicationController
+  before_action :check_license_admin_audit_log_available!
+
   def index
     @events = LogFinder.new(audit_logs_params).execute
     @entity = case audit_logs_params[:event_type]
@@ -16,4 +18,8 @@ class Admin::AuditLogsController < Admin::ApplicationController
   def audit_logs_params
     params.permit(:page, :event_type, :user_id, :project_id, :group_id)
   end
+
+  def check_license_admin_audit_log_available!
+    render_404 unless License.feature_available?(:admin_audit_log)
+  end
 end

app/views/admin/monitoring/_head.html.haml

@@ -27,7 +27,4 @@
           = link_to admin_requests_profiles_path, title: 'Requests Profiles' do
             %span
               Requests Profiles
-        = nav_link path: 'audit_logs#index' do
-          = link_to admin_audit_logs_path, title: 'Audit Log' do
-            %span
-              Audit Log
+        = render 'admin/monitoring/ee/nav'

app/views/admin/monitoring/ee/_nav.html.haml

+- if License.feature_available?(:admin_audit_log)
+  = nav_link path: 'audit_logs#index' do
+    = link_to admin_audit_logs_path, title: 'Audit Log' do
+      %span
+        Audit Log

spec/features/admin/admin_audit_logs_spec.rb

@@ -9,6 +9,29 @@ describe 'Admin::AuditLogs', feature: true, js: true do
     sign_in(create(:admin))
   end
 
+  context 'unlicensed' do
+    before do
+      stub_licensed_features(admin_audit_log: false)
+    end
+
+    it 'returns 404' do
+      visit admin_audit_logs_path
+
+      expect(page.status_code).to eq(404)
+    end
+  end
+
+  context 'licensed' do
+    before do
+      stub_licensed_features(admin_audit_log: true)
+    end
+
+    it 'has Audit Log button in head nav bar' do
+      visit admin_audit_logs_path
+
+      expect(page).to have_link('Audit Log', href: admin_audit_logs_path)
+    end
+
     describe 'user events' do
       before do
         AuditEventService.new(user, user, with: :ldap)
@@ -80,6 +103,7 @@ describe 'Admin::AuditLogs', feature: true, js: true do
         expect(page).to have_content('Removed user access')
       end
     end
+  end
 
   def filter_by_type(type)
     click_button 'Events'