Add EE logic to Add button in clusters/index

app/views/projects/clusters/_tabs.html.haml

@@ -15,4 +15,7 @@
         = s_("ClusterIntegration|All")
         %span.badge= @all_count
   .nav-controls
-    = link_to s_("ClusterIntegration|Add cluster"), new_project_cluster_path(@project), class: "btn btn-success btn-add-cluster disabled has-tooltip js-add-cluster", title: s_("ClusterIntegration|Multiple clusters are available in GitLab Entreprise Edition Premium and Ultimate")
+    - if @project.feature_available?(:multiple_clusters)
+      = link_to s_("ClusterIntegration|Add cluster"), new_project_cluster_path(@project), class: "btn btn-success btn-add-cluster has-tooltip js-add-cluster"
+    - else
+      = link_to s_("ClusterIntegration|Add cluster"), new_project_cluster_path(@project), class: "btn btn-success btn-add-cluster disabled has-tooltip js-add-cluster", title: s_("ClusterIntegration|Multiple clusters are available in GitLab Entreprise Edition Premium and Ultimate")

spec/features/projects/clusters_spec.rb

@@ -35,8 +35,24 @@ feature 'Clusters', :js do
       expect(page).to have_selector('.gl-responsive-table-row', count: 2)
     end
 
-    it 'user sees a disabled add cluster button ' do
-      expect(page).to have_selector('.js-add-cluster.disabled')
+    context 'when license has multiple clusters feature' do
+      before do
+        allow_any_instance_of(EE::Project).to receive(:feature_available?).with(:multiple_clusters).and_return(true)
+      end
+
+      it 'user sees a add cluster button ' do
+        expect(page).to have_selector('.js-add-cluster')
+      end
+    end
+
+    context 'when license does not have multiple clusters feature' do
+      before do
+        allow_any_instance_of(EE::Project).to receive(:feature_available?).with(:multiple_clusters).and_return(false)
+      end
+
+      it 'user sees a disabled add cluster button ' do
+        expect(page).to have_selector('.js-add-cluster.disabled')
+      end
     end
 
     it 'user sees navigation tabs' do