Connect: Allow for a prepared query to be used in more than one envoy upstream

#### Feature Description
We are looking to use the same prepared query in multiple envoy upstream configurations, the difference in those upstreams will be the port and the `envoy_cluster_json` of those upstreams for both timeouts & circuit breaking reasons.

Snippet of our current hcl:
```
...
upstreams = [
{
destination_type = "prepared_query"
destination_name = "our-service-query"
local_bind_port = 9988
config {
envoy_cluster_json = <