### 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_
assert len(sns_backend.platform_endpoint_messages[platform_arn]) > 0
        retry(check_message, retries=PUBLICATION_RETRIES, sleep=PUBLICATION_TIMEOUT)
    @pytest.mark.aws_validated
    def test_unknown_topic_publish(self, sns_client, sns_create_topic, snapshot):
        # c
        # o
        topic_arn = sns_create_topic()["TopicArn"]
        # a
        fake_arn = f"{topic_arn}-fake"
        message = "This is a test message"
        with pytest.raises(ClientError) as e:
            sns_client.publish(TopicArn=fake_arn, Message=message)
        snapshot.match("error", e.value.response)
    @pytest.mark.only_localstack
    def test_publish_sms(self, sns_client):