### 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_
subscriber["SubscriptionArn"],
            )
            response = lambda_api.process_sns_notification(
                subscriber["Endpoint"],
                topic_arn,
                subscriber["SubscriptionArn"],
                message,
                message_id,
                message_attributes,
                unsubscribe_url,
                subject=req_data.get("Subject", [None])[0],
            )
            if response is not None:
                delivery = {
                    "statusCode": response.status_code,
                    "providerResponse": response.get_data(),
                }
                store_delivery_log(subscriber, True, message, message_id, delivery)
            if isinstance(response, Response):
                response.raise_for_status()
            elif isinstance(response, FlaskResponse):
                if response.status_code >= 400:
                    raise Exception(
                        "Error response (code %s): %s" % (response.status_code, response.data)
                    )
        except Exception as exc:
            LOG.info(
                "Unable to run Lambda function on SNS message: %s %s"
                % (exc, traceback.format_exc())
            )