Use existing common metrics

app/controllers/projects/environments_controller.rb

@@ -13,7 +13,6 @@ class Projects::EnvironmentsController < Projects::ApplicationController
   before_action only: [:metrics, :additional_metrics] do
     push_frontend_feature_flag(:metrics_time_window)
     push_frontend_feature_flag(:environment_metrics_use_prometheus_endpoint)
-    push_frontend_feature_flag(:environment_metrics_show_multiple_dashboards)
   end
 
   def index

app/services/metrics_dashboard_service.rb

@@ -2,7 +2,7 @@
 
 # Fetches the metrics dashboard layout and supplemented the output with DB info.
 class MetricsDashboardService
-  SYSTEM_DASHBOARD_NAME = 'system_dashboard'
+  SYSTEM_DASHBOARD_NAME = 'common_metrics'
   SYSTEM_DASHBOARD_PATH = Rails.root.join('config', 'prometheus', "#{SYSTEM_DASHBOARD_NAME}.yml")
 
   def initialize(project)