Envoy sidecar filter config incorrectly generated

#### Overview of the Issue

I have a service within the mesh running with a transparent proxy, and a database outside the service mesh, and I want to connect them through the terminating-gateway. However the envoy sidecar configuration is being generated as if it were an http service, whereas I have set the service up to use tcp by default.

---

#### Reproduction Steps

1. Set up consul service mesh in transparent proxy mode with a terminating gateway
2. Register a dummy service named "my-service" with the consul catalog
3. Register these configuration objects:

```
proxy-defaults:
- protocol: http

service-defaults:
- name: database
- protocol: tcp

terminating-gateway:
- name: tgw
- services:
- name: database

service-intention:
- destination: my-service
- sources:
- name: database
````

4. Start the sidecar for my-service so it retrieves configuration from consul
5. Observe that the configuration contains an http-connection-manager that attempts to route traffic based on the request path and name like so:


6. Observe from the http api that the discovery-chain for database claims that traffic is tcp and not http

I found that the problem could be fixed by overriding the upstream protocol for my-service:

```
service-defaults:
- name: my-service
- protocol: http
- upstreamConfig:
overrides:
- name: database
protocol: tcp
```

Yielding:

I believe that the upstream config is incorrectly coming from the proxy-defaults and not the defaults for the target service.

I also tried with and without specifying a Destination entry on the service-defaults for database, but that did not affect the presence of the http-connection-manager

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### Consul info for both Client and Server

Helm chart: 1.1.1, overridden to use the server 1.15.2 image
Environment: AWS EKS