[x] bug report
[ ] feature request

# Detailed description
`lambda_executor.py` current retrieves the container entrypoint from the docker image via `docker inspect --format="{{ .ContainerConfig.Entrypoint }}" ..`. This is fragile and may be missing depending on how the image in question is built. There is a `config` block _and_ a `containerconfig` block that are mostly the same, but sometimes different depending what built and what version of that thing built the image, for example we are seeing the entrypoint missing on images built with Docker for Mac 2.5.0.1, but not on earlier versions, others using `podman` are noticing the fragility in other projects:

https://github.com/containers/podman/issues/2017

## Expected behavior
entrypoint value is picked up from a validly built container

## Actual behavior
entrypoint is sometimes an empty string, which then for a `provided` lambda executor ends up with a script error trying to execute the handler name.

The simple fix is to change `--format="{{ .ContainerConfig.Entrypoint }}"` to `--format="{{ .Config.Entrypoint }}"` which seems like the more canonical way of getting that value.



┆Issue is synchronized with this [Jira Task](https://localstack.atlassian.net/browse/LOC-54) by [Unito](https://www.unito.io/learn-more)

0 if the container does not exist.
        """
        with self.docker_container_lock:
            
            container_name = self.get_container_name(func_arn)
            
            
            
            cmd = ("docker ps -a --filter name='%s' "
                   '--format "{{ .Status }} - {{ .Names }}" '
                   '| grep -w "%s" | cat') % (container_name, container_name)
            LOG.debug('Getting status for container "%s": %s' % (container_name, cmd))
            cmd_result = run(cmd)
            
            container_status = cmd_result.strip()
            if len(container_status) == 0:
                return 0
            if container_status.lower().startswith('up '):
                return 1
            return -1
    def get_docker_container_network(self, func_arn):
        """
        Determine the network of a docker container.
        :param func_arn: The ARN of the lambda function.
        :return: name of the container network
        """
        with self.docker_container_lock:
            status = self.get_docker_container_status(func_arn)
            
            if status == 0: