### 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_
from localstack.config import external_service_url
from localstack.constants import TEST_AWS_ACCOUNT_ID
from localstack.services.generic_proxy import ProxyListener
from localstack.services.infra import start_proxy
from localstack.services.install import SQS_BACKEND_IMPL
from localstack.services.sns.sns_listener import SNSBackend
from localstack.utils import testutil
from localstack.utils.aws import aws_stack
from localstack.utils.common import (
    get_free_tcp_port,
    get_service_protocol,
    retry,
    short_uid,
    to_str,
    wait_for_port_open,
)
from localstack.utils.testutil import check_expected_lambda_log_events_length
from .lambdas import lambda_integration
from .test_lambda import LAMBDA_RUNTIME_PYTHON36, TEST_LAMBDA_LIBS, TEST_LAMBDA_PYTHON
TEST_TOPIC_NAME = "TestTopic_snsTest"
TEST_QUEUE_NAME = "TestQueue_snsTest"
TEST_QUEUE_DLQ_NAME = "TestQueue_DLQ_snsTest"
TEST_TOPIC_NAME_2 = "topic-test-2"
PUBLICATION_TIMEOUT = 0.500
PUBLICATION_RETRIES = 4
THIS_FOLDER = os.path.dirname(os.path.realpath(__file__))
TEST_LAMBDA_ECHO_FILE = os.path.join(THIS_FOLDER, "lambdas", "lambda_echo.py")
class SNSTest(unittest.TestCase):
    @classmethod
    def setUpClass(cls):