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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)

...

elif result[0] == 's3' or re.match(r'.*s3(\-website)?\.([^\.]+\.)?amazonaws.com', host):
        host = re.sub(r's3-website\..*\.amazonaws', 's3.amazonaws', host)
        result = 's3', config.PORT_S3
    elif result[0] == 'states' in auth_header or host.startswith('states.'):
        result = 'stepfunctions', config.PORT_STEPFUNCTIONS
    elif result[0] == 'monitoring':
        result = 'cloudwatch', config.PORT_CLOUDWATCH
    elif '.execute-api.' in host:
        result = 'apigateway', config.PORT_APIGATEWAY
    elif target.startswith('DynamoDBStreams') or host.startswith('streams.dynamodb.'):
        
        result = result_before = 'dynamodbstreams', config.PORT_DYNAMODBSTREAMS
    elif ls_target == 'web' or path == '/graph':
        result = 'web', config.PORT_WEB_UI
    return result[0], result_before[1] or result[1], path, host
def is_s3_form_data(data_bytes):
    if(to_bytes('key=') in data_bytes):
        return True
    if(to_bytes('Content-Disposition: form-data') in data_bytes and to_bytes('name="key"') in data_bytes):
        return True
    return False
def serve_health_endpoint(method, path, data):
    if method == 'GET':
        reload = 'reload' in path
        return plugins.get_services_health(reload=reload)
    if method == 'PUT':
        data = json.loads(to_str(data))
        plugins.set_services_health(data)
        return {'status': 'OK'}
def get_port_from_custom_rules(method, path, data, headers):