### 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_
return {
            "PhoneNumber": subscriber["Endpoint"],
            "TopicArn": subscriber["TopicArn"],
            "SubscriptionArn": subscriber["SubscriptionArn"],
            "MessageId": message_context.message_id,
            "Message": message_context.message_content(protocol=subscriber["Protocol"]),
            "MessageAttributes": message_context.message_attributes,
            "MessageStructure": message_context.message_structure,
            "Subject": message_context.subject,
        }
class FirehoseTopicPublisher(TopicPublisher):
    """
    The Firehose publisher is responsible for publishing the SNS message to a subscribed Firehose delivery stream.
    This allows you to "fan out Amazon SNS notifications to Amazon Simple Storage Service (Amazon S3), Amazon Redshift,
    Amazon OpenSearch Service (OpenSearch Service), and to third-party service providers."
    See https://docs.aws.amazon.com/sns/latest/dg/sns-firehose-as-subscriber.html
    """
    def _publish(self, context: SnsPublishContext, subscriber: SnsSubscription):