### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

I am using below docker-compose file to start the localstack container with es service
```
version: "3"
services:
  wiremock:
    image: "rodolpheche/wiremock"
    ports:
      - "8080"
  localstack:
    image: "localstack/localstack-full:0.14.2"
    ports:
      - "4566"
      - "4510:4510"
    environment:
      AWS_ACCESS_KEY_ID: "local-access-key-id"
      AWS_SECRET_ACCESS_KEY: "local-secret-access-key"
      HOSTNAME_EXTERNAL: "localstack"
      OPENSEARCH_ENDPOINT_STRATEGY: "port"
      SERVICES: "es"
      EDGE_PORT: "4566"
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"

```

running `aws --region ap-south-1 --endpoint-url http://localstack:4566 es create-elasticsearch-domain --domain-name my-domain` to create domain
this command is returning `localhost:4510` as an endpoint, I am able to curl `curl localhost:4510` within localstack bash but 
neither on the host machine nor in `wiremock` container.



### Expected Behavior

I should able to access elastic search domain in host machine as well in another container

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

#### How are you starting localstack

 ```
version: "3"
services:
  wiremock:
    image: "rodolpheche/wiremock"
    ports:
      - "8080"
  localstack:
    image: "localstack/localstack-full:0.14.2"
    ports:
      - "4566"
      - "4510:4510"
    environment:
      AWS_ACCESS_KEY_ID: "local-access-key-id"
      AWS_SECRET_ACCESS_KEY: "local-secret-access-key"
      HOSTNAME_EXTERNAL: "localstack"
      OPENSEARCH_ENDPOINT_STRATEGY: "port"
      SERVICES: "es"
      EDGE_PORT: "4566"
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"

```

#### Client commands

    aws --region ap-south-1 --endpoint-url http://localstack:4566 es create-elasticsearch-domain --domain-name my-domain


### Environment

```markdown
- OS:
- LocalStack:
```


### Anything else?

_No response_
class TestCustomBackendManager:
    def test_custom_backend(self, httpserver, monkeypatch):
        monkeypatch.setattr(config, "OPENSEARCH_ENDPOINT_STRATEGY", "domain")
        monkeypatch.setattr(config, "OPENSEARCH_CUSTOM_BACKEND", httpserver.url_for("/"))
        
        httpserver.expect_request("/").respond_with_json(
            {
                "name": "om",
                "cluster_name": "opensearch",
                "cluster_uuid": "gREewvVZR0mIswR-8-6VRQ",
                "version": {
                    "number": "7.10.0",
                    "build_flavor": "default",
                    "build_type": "tar",
                    "build_hash": "51e9d6f22758d0374a0f3f5c6e8f3a7997850f96",
                    "build_date": "2020-11-09T21:30:33.964949Z",
                    "build_snapshot": False,
                    "lucene_version": "8.7.0",
                    "minimum_wire_compatibility_version": "6.8.0",
                    "minimum_index_compatibility_version": "6.0.0-beta1",
                },
                "tagline": "You Know, for Search",
            }
        )
        httpserver.expect_request("/_cluster/health").respond_with_json(
            {
                "cluster_name": "opensearch",
                "status": "green",
                "timed_out": False,
                "number_of_nodes": 1,