### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

It seems that it is possible to receive sns message in an sqs listener if there is a filterpolicy in place for null value in a message attribute, and a message is being sent without the message attribute.

### Expected Behavior

Don't recieve these type of messages

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

`sns subscribe --topic-arn "demoTopicArn"  --protocol sqs --notification-endpoint "demoSqsEndpoint" --attributes '{"RawMessageDelivery": "true"}'`
`sns set-subscription-attributes --subscription-arn demoSubsArn --attribute-name FilterPolicy --attribute-value '{"testForNull": [null,{"anything-but": ["notgood"]}]}'`
`sns publish --topic-arn demoTopicArn --message "testforrecieval"`
`sqs receive-message --queue-url  "demoUrl"`

### Environment

```markdown
- OS: macOS 13.6
- LocalStack: 2.2.0
```


### Anything else?

_No response_
"""
        Base method for publishing the message. It is up to the child class to implement its way to publish the message
        :param context: the SnsPublishContext created by the caller, containing the necessary data to publish the
        message
        :param subscriber: the subscription data
        :return:
        """
        raise NotImplementedError
    def prepare_message(self, message_context: SnsMessage, subscriber: SnsSubscription) -> str:
        """
        Returns the message formatted in the base SNS message format. The base SNS message format is shared amongst
        SQS, HTTP(S), email-json and Firehose.
        See https://docs.aws.amazon.com/sns/latest/dg/sns-sqs-as-subscriber.html
        :param message_context: the SnsMessage containing the message data
        :param subscriber: the SNS subscription
        :return: formatted SNS message body in a JSON string
        """
        return create_sns_message_body(message_context, subscriber)
class EndpointPublisher(abc.ABC):