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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)

...

port = port or config.PORT_SQS
    install_elasticmq()
    PORT_SQS_BACKEND = get_free_tcp_port()
    
    config_params = """
    include classpath("application.conf")
    node-address {
        protocol = http
        host = "%s"
        port = %s
        context-path = ""
    }
    rest-sqs {
        enabled = true
        bind-port = %s
        bind-hostname = "0.0.0.0"
        sqs-limits = strict
    }
    """ % (LOCALSTACK_HOSTNAME, port, PORT_SQS_BACKEND)
    config_file = os.path.join(TMP_FOLDER, 'sqs.%s.conf' % short_uid())
    TMP_FILES.append(config_file)
    save_file(config_file, config_params)
    
    cmd = ('java -Dconfig.file=%s -Xmx%s -jar %s/elasticmq-server.jar' % (
        config_file, MAX_HEAP_SIZE, INSTALL_DIR_ELASTICMQ))
    print('Starting mock SQS service in %s ports %s (recommended) and %s (deprecated)...' % (
        get_service_protocol(), config.EDGE_PORT, port))
    start_proxy_for_service('sqs', port, PORT_SQS_BACKEND, update_listener)
    return do_run(cmd, asynchronous)