Preview: Propagated connections support Private Service Connect

## Feature Feature **Preview**: [Propagated connections](https://cloud.google.com/vpc/docs/about-propagated-connections)support Private Service Connect[endpoints that access global Google APIs](https://cloud.google.com/vpc/docs/about-accessing-google-apis-endpoints). With propagated connections, endpoints that access global Google APIs in one consumer VPC spoke can be privately accessed by other consumer VPC spokes that are connected to the same Network Connectivity Center hub.