### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

I am running an SNS topic that publishes to a lambda function. The localstack code reads a type byte object from the lambda function invocation payload [here](https://github.com/localstack/localstack/blob/master/localstack/services/sns/publisher.py#L187) and then tries to dump the result into json [here](https://github.com/localstack/localstack/blob/master/localstack/services/sns/publisher.py#L863) which results in the following error:
```
sns_pub_0] l.services.sns.publisher   : Unable to run Lambda function on SNS message: Object of type bytes is not JSON serializable
```

### Expected Behavior

The payload bytes should be converted to a string before being dumped to json. The error should not be thrown.

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

docker-compose up
(Using the standard docker-compose.yaml)

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

```
awslocal sns publish --message file://sns/message.json --topic-arn arn:aws:sns:us-east-1:000000000000:<topic_name>
```

### Environment

```markdown
- OS: macOS Ventura 13.2.1
- LocalStack: latest
```


### Anything else?

_No response_
is_endpoint_publish = target_arn and ":endpoint/" in target_arn
        if message_structure == "json":
            try:
                message = json.loads(message)
                
                
                if "default" not in message and not is_endpoint_publish:
                    raise InvalidParameterException(
                        "Invalid parameter: Message Structure - No default entry in JSON message body"
                    )
            except json.JSONDecodeError:
                raise InvalidParameterException(
                    "Invalid parameter: Message Structure - JSON message body failed to parse"
                )
        if message_attributes:
            validate_message_attributes(message_attributes)
        store = self.get_store()
        if not phone_number:
            if is_endpoint_publish:
                moto_sns_backend = sns_backends[context.account_id][context.region]
                if target_arn not in moto_sns_backend.platform_endpoints:
                    raise InvalidParameterException(
                        "Invalid parameter: TargetArn Reason: No endpoint found for the target arn specified"
                    )
            else:
                if topic_or_target_arn not in store.sns_subscriptions:
                    raise NotFoundException(
                        "Topic does not exist",
                    )
        message_ctx = SnsMessage(