[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)

def execute_java_lambda(self, event, context, main_file, func_details=None):
        handler = func_details.handler
        opts = config.LAMBDA_JAVA_OPTS if config.LAMBDA_JAVA_OPTS else ''
        event_file = EVENT_FILE_PATTERN.replace('*', short_uid())
        save_file(event_file, json.dumps(json_safe(event)))
        TMP_FILES.append(event_file)
        class_name = handler.split('::')[0]
        classpath = '%s:%s:%s' % (main_file, Util.get_java_classpath(main_file), LAMBDA_EXECUTOR_JAR)
        cmd = 'java %s -cp %s %s %s %s' % (opts, classpath, LAMBDA_EXECUTOR_CLASS, class_name, event_file)
        LOG.warning(cmd)
        result = self.run_lambda_executor(cmd, func_details=func_details)
        return result
class Util:
    debug_java_port = False
    @classmethod
    def get_java_opts(cls):
        opts = config.LAMBDA_JAVA_OPTS or ''
        
        if '_debug_port_' in opts:
            if not cls.debug_java_port:
                cls.debug_java_port = get_free_tcp_port()
            opts = opts.replace('_debug_port_', ('%s' % cls.debug_java_port))
        else:
            
            m = re.match('.*address=(.+:)?(\\d+).*', opts)
            if m is not None:
                cls.debug_java_port = m.groups()[1]
        return opts
    @classmethod
    def get_host_path_for_path_in_docker(cls, path):