### 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_
fake_arn = "arn:aws:sns:us-east-1:123456789012:i_dont_exist"
        message = "This is a test message"
        try:
            self.sns_client.publish(TopicArn=fake_arn, Message=message)
            self.fail("This call should not be successful as the topic does not exist")
        except ClientError as e:
            self.assertEqual(e.response["Error"]["Code"], "NotFound")
            self.assertEqual(e.response["Error"]["Message"], "Topic does not exist")
            self.assertEqual(e.response["ResponseMetadata"]["HTTPStatusCode"], 404)
    def test_publish_sms(self):
        response = self.sns_client.publish(PhoneNumber="+33000000000", Message="This is a SMS")
        self.assertTrue("MessageId" in response)
        self.assertEqual(response["ResponseMetadata"]["HTTPStatusCode"], 200)
    def test_publish_target(self):
        response = self.sns_client.publish(
            TargetArn="arn:aws:sns:us-east-1:000000000000:endpoint/APNS/abcdef/0f7d5971-aa8b-4bd5-b585-0826e9f93a66",
            Message="This is a push notification",
        )
        self.assertTrue("MessageId" in response)
        self.assertEqual(response["ResponseMetadata"]["HTTPStatusCode"], 200)
    def test_tags(self):
        self.sns_client.tag_resource(
            ResourceArn=self.topic_arn,
            Tags=[
                {"Key": "123", "Value": "abc"},
                {"Key": "456", "Value": "def"},
                {"Key": "456", "Value": "def"},
            ],