### 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_
assert "SigningCertURL" in payload
        token = payload["Token"]
        assert payload["URL"] == (
            f"{service_url}/?" f"Action=ConfirmSubscription&TopicArn={topic_arn}&Token={token}"
        )
        snapshot.match("unsubscribe-request", payload)
    @markers.aws.manual_setup_required
    @pytest.mark.parametrize("raw_message_delivery", [True, False])
    def test_dlq_external_http_endpoint(
        self,
        sqs_create_queue,
        sqs_get_queue_arn,
        sns_create_http_endpoint,
        sns_allow_topic_sqs_queue,
        raw_message_delivery,
        aws_client,
    ):
        # N
        topic_arn, http_subscription_arn, endpoint_url, server = sns_create_http_endpoint(
            raw_message_delivery
        )
        dlq_url = sqs_create_queue()
        dlq_arn = sqs_get_queue_arn(dlq_url)
        sns_allow_topic_sqs_queue(
            sqs_queue_url=dlq_url, sqs_queue_arn=dlq_arn, sns_topic_arn=topic_arn
        )
        aws_client.sns.set_subscription_attributes(
            SubscriptionArn=http_subscription_arn,
            AttributeName="RedrivePolicy",
            AttributeValue=json.dumps({"deadLetterTargetArn": dlq_arn}),