### Is there an existing issue for this?

- [X] I have searched the existing issues

### Feature description

Hello team. Please, kindly work on this feature for awslocal CLI:

awslocal es update-elasticsearch-domain-config --domain-name my-domain --region us-east-1 \
      --advanced-security-options '{ "Enabled": true, "InternalUserDatabaseEnabled":true, "MasterUserOptions": {"MasterUserName":"master-username","MasterUserPassword":"master-password"},"AnonymousAuthEnabled": true}'
      
 Right now it returns the following response:
 
An error occurred (InternalFailure) when calling the UpdateElasticsearchDomainConfig operation: API action 'UpdateElasticsearchDomainConfig' for service 'es' not yet implemented
 
 Thank you,
 Victor

### 🧑‍💻 Implementation

_No response_

### Anything else?

_No response_
call_safe(cluster_1.shutdown)
@pytest.mark.skip_offline
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",