Change feature flag to project gate

app/controllers/projects/environments_controller.rb

@@ -14,7 +14,7 @@ class Projects::EnvironmentsController < Projects::ApplicationController
   before_action :expire_etag_cache, only: [:index], unless: -> { request.format.json? }
   before_action only: [:metrics, :additional_metrics, :metrics_dashboard] do
     push_frontend_feature_flag(:prometheus_computed_alerts)
-    push_frontend_feature_flag(:metrics_dashboard_annotations)
+    push_frontend_feature_flag(:metrics_dashboard_annotations, project)
   end
   after_action :expire_etag_cache, only: [:cancel_auto_stop]