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# Type of request: This is a ...

[x] bug report
[ ] feature request

# Detailed description

In the `ReceiveMessageResult` of the SQS service, I saw this XML from localstack:

```
...
<MessageAttribute>
     <Name>encoding</Name>
    <Value>
        <DataType>String</DataType>
        <StringValue><![CDATA[gzip]]></StringValue>
    </Value>
</MessageAttribute>
...
```

The `<![CDATA[gzip]]>` is slightly different from AWS, which doesn't wrap the value in a `<!CDATA[[]]>` section. This shouldn't be a problem for XML parsers that accept both plain characters and CDATA sections for this element, but the XML parser I was using did not, which causes an error when running the code against localstack but not when running the code against AWS. There is obviously a bug in the XML parser as well, but I thought that I should at least post this here since it is different than what AWS SQS does.

## Expected behavior

MessageAttribute::Value elements should not be wrapped in `CDATA` sections.

## Actual behavior

MessageAttribute::Value elements all seem to be wrapped in `CDATA` sections.

# Steps to reproduce

Send a message to the SQS service which contains some custom message attributes, then make a ReceiveMessageRequest.

## Command used to start LocalStack

`docker run --env "SERVICES=sqs" localstack/localstack`

## Client code (AWS SDK code snippet, or sequence of "awslocal" commands)

...

LOG.debug('Priming docker container (status "%s"): %s' % (status, container_name))
            docker_image = Util.docker_image_for_runtime(runtime)
            rm_flag = Util.get_docker_remove_flag()
            
            if status < 1:
                
                self.destroy_docker_container(func_arn)
                env_vars_str = ' '.join(['-e {}={}'.format(k, cmd_quote(v)) for (k, v) in env_vars])
                network = config.LAMBDA_DOCKER_NETWORK
                network_str = '--network="%s"' % network if network else ''
                mount_volume = not config.LAMBDA_REMOTE_DOCKER
                lambda_cwd_on_host = Util.get_host_path_for_path_in_docker(lambda_cwd)
                if (':' in lambda_cwd and '\\' in lambda_cwd):
                    lambda_cwd_on_host = Util.format_windows_path(lambda_cwd_on_host)
                mount_volume_str = '-v "%s":/var/task' % lambda_cwd_on_host if mount_volume else ''
                
                LOG.debug('Creating container: %s' % container_name)
                cmd = (
                    '%s create'
                    ' %s'  
                    ' --name "%s"'
                    ' --entrypoint /bin/bash'  
                    ' %s'
                    ' --interactive'  
                    ' -e AWS_LAMBDA_EVENT_BODY="$AWS_LAMBDA_EVENT_BODY"'
                    ' -e HOSTNAME="$HOSTNAME"'
                    ' -e LOCALSTACK_HOSTNAME="$LOCALSTACK_HOSTNAME"'
                    '  %s'  
                    '  %s'  
                    ' %s'