### 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_
if req_action == "Subscribe" and response.status_code < 400:
                response_data = xmltodict.parse(response.content)
                topic_arn = (req_data.get("TargetArn") or req_data.get("TopicArn"))[0]
                filter_policy = (req_data.get("FilterPolicy") or [None])[0]
                attributes = get_subscribe_attributes(req_data)
                sub_arn = response_data["SubscribeResponse"]["SubscribeResult"]["SubscriptionArn"]
                do_subscribe(
                    topic_arn,
                    req_data["Endpoint"][0],
                    req_data["Protocol"][0],
                    sub_arn,
                    attributes,
                    filter_policy,
                )
            if req_action == "CreateTopic" and response.status_code < 400:
                response_data = xmltodict.parse(response.content)
                topic_arn = response_data["CreateTopicResponse"]["CreateTopicResult"]["TopicArn"]
                
                event_publisher.fire_event(
                    event_publisher.EVENT_SNS_CREATE_TOPIC,
                    payload={"t": event_publisher.get_hash(topic_arn)},
                )
            if req_action == "DeleteTopic" and response.status_code < 400:
                
                topic_arn = (req_data.get("TargetArn") or req_data.get("TopicArn"))[0]
                event_publisher.fire_event(
                    event_publisher.EVENT_SNS_DELETE_TOPIC,
                    payload={"t": event_publisher.get_hash(topic_arn)},
                )
    def should_persist(self, method, path, data, headers, response):