### 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_
"""
    The email-json publisher is responsible for publishing the SNS message to a subscribed email address.
    The format of the message will be JSON-encoded, and "is meant for applications to programmatically process emails".
    There is not a lot of AWS documentation on SNS emails.
    See https://docs.aws.amazon.com/sns/latest/dg/sns-email-notifications.html
    But it is mentioned several times in the SNS FAQ (especially in #Transports section):
    https://aws.amazon.com/sns/faqs/
    """
    def _publish(self, context: SnsPublishContext, subscriber: SnsSubscription):
        ses_client = aws_stack.connect_to_service("ses")
        if endpoint := subscriber.get("Endpoint"):
            ses_client.verify_email_address(EmailAddress=endpoint)
            ses_client.verify_email_address(EmailAddress="admin@localstack.com")
            message_body = self.prepare_message(context.message, subscriber)
            ses_client.send_email(
                Source="admin@localstack.com",
                Message={
                    "Body": {"Text": {"Data": message_body}},
                    "Subject": {"Data": "SNS-Subscriber-Endpoint"},
                },
                Destination={"ToAddresses": [endpoint]},
            )
            store_delivery_log(context.message, subscriber, success=True)
class EmailTopicPublisher(EmailJsonTopicPublisher):