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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)

...

super(LambdaExecutorSeparateContainers, self).__init__()
        self.next_port = 1
        self.max_port = LAMBDA_API_UNIQUE_PORTS
        self.port_offset = LAMBDA_API_PORT_OFFSET
    def prepare_event(self, environment, event_body):
        
        environment['DOCKER_LAMBDA_USE_STDIN'] = '1'
        return event_body.encode()
    def prepare_execution(self, func_arn, env_vars, runtime, command, handler, lambda_cwd):
        entrypoint = ''
        if command:
            entrypoint = ' --entrypoint ""'
        else:
            command = '"%s"' % handler
        
        network = config.LAMBDA_DOCKER_NETWORK
        network_str = '--network="%s"' % network if network else ''
        if network == 'host':
            port = str(self.next_port + self.port_offset)
            env_vars['DOCKER_LAMBDA_API_PORT'] = port
            env_vars['DOCKER_LAMBDA_RUNTIME_PORT'] = port
            self.next_port = (self.next_port + 1) % self.max_port
        env_vars_string = ' '.join(['-e {}="${}"'.format(k, k) for (k, v) in env_vars.items()])