Add missing argument to page object method

Add count argument to has_detailed_specs method
Refactor performance_bar_spec

qa/qa/page/layout/performance_bar.rb

@@ -21,7 +21,7 @@ module QA
           has_element?(:performance_bar)
         end
 
-        def has_detailed_metrics?
+        def has_detailed_metrics?(count)
           retry_until(sleep_interval: 1) do
             all_elements(:detailed_metric_content, count: count).all? do |metric|
               metric.has_text?(%r{\d+})

qa/qa/specs/features/browser_ui/non_devops/performance_bar_spec.rb

 # frozen_string_literal: true
 
 module QA
-  context 'Performance bar' do
-    context 'when logged in as an admin user', :requires_admin, quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/196141' do
+  context 'Non-devops' do
+    describe 'Performance bar display', :requires_admin, quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/196141' do
+      context 'when logged in as an admin user' do
+        # 4 metrics: pg, gitaly, redis, total
+        let(:metrics_count) { 4 }
+
         before do
           Flow::Login.sign_in_as_admin
           Page::Main::Menu.perform(&:go_to_admin_area)
@@ -24,10 +28,11 @@ module QA
 
           Page::Layout::PerformanceBar.perform do |bar_component|
             expect(bar_component).to have_performance_bar
-          expect(bar_component).to have_detailed_metrics(4)
+            expect(bar_component).to have_detailed_metrics(metrics_count)
             expect(bar_component).to have_request_for('realtime_changes') # Always requested on issue pages
           end
         end
       end
     end
+  end
 end