### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

When you publish a message to SNS without a *body* (e.g. only attributes) it succeeds.

### Expected Behavior

Trying to publish a message without a *body* should fail (at least it does when trying to do this in AWS)

### How are you starting LocalStack?

Custom (please describe below)

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

using Java testcontainers...

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

```bash
#!/bin/sh
 
queue_arn=$(awslocal sqs create-queue --queue-name $QUEUE_NAME --output text)
echo "Queue ARN: $queue_arn"

topic_arn=$(awslocal sns create-topic --name $TOPIC_NAME --output text)
echo "Topic ARN: $topic_arn"

subscription_arn=$(awslocal sns subscribe \
    --attributes RawMessageDelivery=true \
    --topic-arn "$topic_arn" \
    --protocol sqs \
    --notification-endpoint "$queue_arn" \
    --output text)
echo "Subscription ARN: $subscription_arn" 
```


### Environment

```markdown
- OS: OSX 11.5.2
- LocalStack: 0.13.0
- Docker Desktop: v20.10.8
```


### Anything else?

_No response_
response = self.sns_client.create_topic(Name=TEST_TOPIC_NAME)
        topic_arn_params = response["TopicArn"].split(":")
        self.assertEqual(topic_arn_params[4], TEST_AWS_ACCOUNT_ID)
        self.assertEqual(topic_arn_params[5], TEST_TOPIC_NAME)
    def test_publish_message_by_target_arn(self):
        self.unsubscribe_all_from_sns()
        topic_name = "queue-{}".format(short_uid())
        func_name = "lambda-%s" % short_uid()
        topic_arn = self.sns_client.create_topic(Name=topic_name)["TopicArn"]
        testutil.create_lambda_function(
            handler_file=TEST_LAMBDA_ECHO_FILE,
            func_name=func_name,
            runtime=LAMBDA_RUNTIME_PYTHON36,
        )
        lambda_arn = aws_stack.lambda_function_arn(func_name)
        subscription_arn = self.sns_client.subscribe(
            TopicArn=topic_arn, Protocol="lambda", Endpoint=lambda_arn
        )["SubscriptionArn"]
        self.sns_client.publish(
            TopicArn=topic_arn, Message="test_message_1", Subject="test subject"
        )