### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

- following the [installation steps](https://docs.localstack.cloud/getting-started/installation/) fails when validating localstack configuration

- error
![image](https://github.com/localstack/localstack/assets/10324554/d82ef62e-c8b8-402e-8195-e691733cfeb1)

- localstack is indeed running
![image](https://github.com/localstack/localstack/assets/10324554/44d7180a-5090-416d-afa9-c4eaaedca33e)


### Expected Behavior

- localstack can consume the path I pass `--file`

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

    docker compose up -d
    localstack config validate --file ./compose.yaml


### Environment

```markdown
OS: Ubuntu 20.04
    LocalStack: latest
```


### Anything else?

- you can reproduce [on this branch](https://github.com/noahehall/localstack/tree/rds) if it still exists
  - else switch to the develop branch
self.name = name or config.MAIN_CONTAINER_NAME
        self.entrypoint = os.environ.get("ENTRYPOINT", "")
        self.command = shlex.split(os.environ.get("CMD", ""))
        self.image_name = get_docker_image_to_start()
        self.ports = PortMappings(bind_host=config.EDGE_BIND_HOST)
        self.volumes = VolumeMappings()
        self.env_vars = {}
        self.additional_flags = []
        self.logfile = os.path.join(config.dirs.tmp, f"{self.name}_container.log")
    def _get_mount_volumes(self) -> List[SimpleVolumeBind]:
        
        mount_volumes = []
        for volume in self.volumes:
            if isinstance(volume, tuple):
                mount_volumes.append(volume)
            elif isinstance(volume, VolumeBind):
                mount_volumes.append((volume.host_dir, volume.container_dir))
            else:
                raise NotImplementedError("no support for volume type %s" % type(volume))
        return mount_volumes
    def run(self):
        if isinstance(DOCKER_CLIENT, CmdDockerClient):
            DOCKER_CLIENT.default_run_outfile = self.logfile
        try:
            return DOCKER_CLIENT.run_container(
                image_name=self.image_name,
                stdin=self.stdin,