### 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_
self,
        context: RequestContext,
        platform_application_arn: String,
        token: String,
        custom_user_data: String = None,
        attributes: MapStringToString = None,
    ) -> CreateEndpointResponse:
        
        
        try:
            result: CreateEndpointResponse = call_moto(context)
        except CommonServiceException as e:
            
            if "DuplicateEndpoint" in e.code:
                moto_sns_backend = sns_backends[context.account_id][context.region]
                for e in moto_sns_backend.platform_endpoints.values():
                    if e.token == token:
                        if custom_user_data and custom_user_data != e.custom_user_data:
                            
                            raise CommonServiceException(
                                code="DuplicateEndpoint",
                                message=f"Endpoint already exist for token: {token} with different attributes",
                            )
            raise
        return result
    def unsubscribe(self, context: RequestContext, subscription_arn: subscriptionARN) -> None: