### 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_platform_application(
            Name="test-%s" % short_uid(),
            Platform="GCM",
            Attributes={"PlatformCredential": "123"},
        )
        kwargs_list = [
            {"Token": "test1", "CustomUserData": "test-data"},
            {"Token": "test1", "CustomUserData": "test-data"},
            {"Token": "test1"},
            {"Token": "test1"},
        ]
        platform_arn = response["PlatformApplicationArn"]
        responses = []
        for kwargs in kwargs_list:
            responses.append(
                self.sns_client.create_platform_endpoint(
                    PlatformApplicationArn=platform_arn, **kwargs
                )
            )
        # A
        for i in range(len(responses)):
            self.assertIn("EndpointArn", responses[i])
        endpoint_arn = responses[0]["EndpointArn"]
        # c
        self.sns_client.delete_endpoint(EndpointArn=endpoint_arn)
        self.sns_client.delete_platform_application(PlatformApplicationArn=platform_arn)
    def test_publish_by_path_parameters(self):