### 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_
inv_result = lambda_client.invoke(
                FunctionName=subscriber["Endpoint"],
                Payload=to_bytes(event),
                InvocationType=InvocationType.RequestResponse
                if config.SYNCHRONOUS_SNS_EVENTS
                else InvocationType.Event,  
            )
            status_code = inv_result.get("StatusCode")
            payload = inv_result.get("Payload")
            if payload:
                delivery = {
                    "statusCode": status_code,
                    "providerResponse": payload.read(),
                }
                store_delivery_log(context.message, subscriber, success=True, delivery=delivery)
        except Exception as exc:
            LOG.info(
                "Unable to run Lambda function on SNS message: %s %s", exc, traceback.format_exc()
            )
            store_delivery_log(context.message, subscriber, success=False)
            message_body = create_sns_message_body(
                message_context=context.message, subscriber=subscriber
            )
            sns_error_to_dead_letter_queue(subscriber, message_body, str(exc))
    def prepare_message(self, message_context: SnsMessage, subscriber: SnsSubscription) -> str:
        """
        You can see Lambda SNS Event format here: https://docs.aws.amazon.com/lambda/latest/dg/with-sns.html
        :param message_context: the SnsMessage containing the message data
        :param subscriber: the SNS subscription
        :return: an SNS message body formatted as a lambda Event in a JSON string