Add spec for multiple metrics in response

spec/lib/gitlab/metrics/dashboard/processor_spec.rb

@@ -74,6 +74,16 @@ describe Gitlab::Metrics::Dashboard::Processor do
         expect(actual_metrics_order).to eq expected_metrics_order
       end
 
+      context 'when the project has multiple metrics in the same group' do
+        let!(:project_response_metric) { create(:prometheus_metric, project: project, group: :response) }
+        let!(:project_response_metric_2) { create(:prometheus_metric, project: project, group: :response) }
+
+        it 'includes multiple metrics' do
+          expect(all_metrics).to include get_metric_details(project_response_metric)
+          expect(all_metrics).to include get_metric_details(project_response_metric_2)
+        end
+      end
+
       context 'when the dashboard should not include project metrics' do
         let(:sequence) do
           [