Service-Defaults not applied to prepared query upstreams

#### Overview of the Issue

I'm trying to use `service-defaults` config entries to increase the Envoy sidecar Max Connection limits as documented here:
https://www.consul.io/docs/connect/config-entries/service-defaults

My upstreams are defined using prepared queries (because I need to lookup specific instances of services via tag).

UpstreamConfig defaults appear to be ignored for any upstreams defined using prepared queries rather than the plain service lookup.

#### Reproduction Steps

Kubernetes manifests and terraform example I used to create config entries and prepared query
https://gist.github.com/hamishforbes/39aeecc466a3b314a7d628f07f005948

tl;dr: 2 upstreams on the client pod, one for `server` and one for `prepared_query:test_server`
The prepared query just looks for `server` services tagged `test`.
The `service-defaults` entry for the `client` service sets `UpstreamConfig.Defaults.Limits.MaxConnections = 2000`

The upstream cluster for the prepared query does not pickup the configuration but the plain cluster does
```
> k exec -it (k get pod -lname=client -o jsonpath="{.items[0].metadata.name}") -c client -- curl localhost:19000/clusters | grep 'consul::default_priority::max_connections'
c0657655~server.default.ap-southeast-2.internal.c0aedc2c-bb39-3212-2849-82e71c5640db.consul::default_priority::max_connections::2000
test.server.default.ap-southeast-2.query.c0aedc2c-bb39-3212-2849-82e71c5640db.consul::default_priority::max_connections::1024
````

The prepared query returns the same service as the plain lookup (snipped some output for brevity)

```
> curl -s -H"X-Consul-Token: $CONSUL_HTTP_TOKEN" "$CONSUL_HTTP_ADDR/v1/query/test_server/execute?dc=ap-southeast-2" | jq '.Nodes[0].Service'
{
"ID": "server-647f5d445c-g6mgc-server",
"Service": "server",
"Tags": [
"test"
],
...
"Meta": {
"k8s-namespace": "test",
"k8s-service-name": "server",
"managed-by": "consul-k8s-endpoints-controller",
"pod-name": "server-647f5d445c-g6mgc"
},
...
}
```

```
> curl -s -H"X-Consul-Token: $CONSUL_HTTP_TOKEN" "$CONSUL_HTTP_ADDR/v1/catalog/service/server?dc=ap-southeast-2" | jq
[
{
...
"ServiceID": "server-647f5d445c-g6mgc-server",
"ServiceName": "server",
"ServiceTags": [
"test"
],
...
"ServiceMeta": {
"k8s-namespace": "test",
"k8s-service-name": "server",
"managed-by": "consul-k8s-endpoints-controller",
"pod-name": "server-647f5d445c-g6mgc"
},
...
}
]
```

### Consul info for both Client and Server

Consul 1.10.4 client and server

consul-k8s integration installed via Helm - v0.37.0