fix: update golden list of metrics

test/instrumentation/testdata/stable-metrics-list.yaml

@@ -256,6 +256,12 @@
   labels:
   - deprecated_version
   - stability_level
+- name: route_sync_total
+  subsystem: route_controller
+  help: A metric counting the amount of times routes have been synced with the cloud
+    provider.
+  type: Counter
+  stabilityLevel: BETA
 - name: pod_scheduling_sli_duration_seconds
   subsystem: scheduler
   help: E2e latency for a pod being scheduled, from the time the pod enters the scheduling