Fix bugs in GKE monitoring and healthcheck config

Author: liu-cong

config/charts/inferencepool/values.yaml

@@ -50,6 +50,8 @@ inferenceExtension:
     # Prometheus ServiceMonitor will be created when enabled for EPP metrics collection
     prometheus:
       enabled: false
+    gke:
+      enabled: false
 
 inferencePool:
   targetPorts: