Support Setting Autoscaling Metrics when deploying Model to an Endpoint with python api

https://cloud.google.com/vertex-ai/docs/predictions/configure-compute#scaling

### References
- https://cloud.google.com/vertex-ai/docs/reference/rest/v1/projects.locations.endpoints#deployedmodel
-https://cloud.google.com/vertex-ai/docs/reference/rest/v1/DedicatedResources
- https://cloud.google.com/vertex-ai/docs/reference/rest/v1/DedicatedResources#AutoscalingMetricSpec
