### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

`PORTS_CHECK_DOCKER_IMAGE` is not configurable which prevents ECS tasks from running on air-gapped environment



### Expected Behavior

`PORTS_CHECK_DOCKER_IMAGE` can be configured via configuration option to allow use of any available image 

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

Run an ECS task in an environment where localstack/localstack is not available.

### Environment

```markdown
- OS: RHEL8
- Docker runtime version: Podman v4.2.0
- LocalStack: 1.3.1
```


### Anything else?

_No response_
"KINESIS_ON_DEMAND_STREAM_COUNT_LIMIT",
    "LAMBDA_CODE_EXTRACT_TIME",
    "LAMBDA_CONTAINER_REGISTRY",
    "LAMBDA_DOCKER_DNS",
    "LAMBDA_DOCKER_FLAGS",
    "LAMBDA_DOCKER_NETWORK",
    "LAMBDA_EXECUTOR",
    "LAMBDA_FALLBACK_URL",
    "LAMBDA_FORWARD_URL",
    "LAMBDA_RUNTIME_IMAGE_MAPPING",
    "LAMBDA_JAVA_OPTS",
    "LAMBDA_REMOTE_DOCKER",
    "LAMBDA_REMOVE_CONTAINERS",
    "LAMBDA_DEV_PORT_EXPOSE",
    "LAMBDA_RUNTIME_EXECUTOR",
    "LAMBDA_RUNTIME_ENVIRONMENT_TIMEOUT",
    "LAMBDA_STAY_OPEN_MODE",
    "LAMBDA_TRUNCATE_STDOUT",
    "LAMBDA_RETRY_BASE_DELAY_SECONDS",
    "LAMBDA_SYNCHRONOUS_CREATE",
    "LEGACY_DIRECTORIES",
    "LEGACY_DOCKER_CLIENT",
    "LEGACY_EDGE_PROXY",
    "LEGACY_SNS_GCM_PUBLISHING",
    "LOCALSTACK_API_KEY",
    "LOCALSTACK_HOSTNAME",
    "LOG_LICENSE_ISSUES",
    "LS_LOG",
    "MAIN_CONTAINER_NAME",
    "OPENSEARCH_ENDPOINT_STRATEGY",