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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)

...

"""
        Starts a repeating timer that triggers start_idle_container_destroyer_interval every 60 seconds.
        Thus checking for idle containers and destroying them.
        :return: None
        """
        self.idle_container_destroyer()
        threading.Timer(60.0, self.start_idle_container_destroyer_interval).start()
    def get_container_name(self, func_arn):
        """
        Given a function ARN, returns a valid docker container name.
        :param func_arn: The ARN of the lambda function.
        :return: A docker compatible name for the arn.
        """
        return 'localstack_lambda_' + re.sub(r'[^a-zA-Z0-9_.-]', '_', func_arn)
class LambdaExecutorSeparateContainers(LambdaExecutorContainers):
    def __init__(self):