### 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_
},
        }
        # p
        sns_client.publish(
            TopicArn=topic_arn,
            Message=message_for_topic_string,
            MessageAttributes=message_attributes,
            MessageStructure="json",
        )
        # p
        sns_client.publish(
            TargetArn=endpoint_arn_2,
            Message=message,
            MessageAttributes=message_attributes,
            MessageStructure="json",
        )
        # a
        def check_message():
            assert len(sns_backend.platform_endpoint_messages[endpoint_arn]) > 0
        retry(check_message, retries=PUBLICATION_RETRIES, sleep=PUBLICATION_TIMEOUT)
        msgs_url = config.get_edge_url() + PLATFORM_ENDPOINT_MSGS_ENDPOINT
        api_contents = requests.get(msgs_url).json()
        api_platform_endpoints_msgs = api_contents["platform_endpoint_messages"]
        assert len(api_platform_endpoints_msgs) == 2
        assert len(api_platform_endpoints_msgs[endpoint_arn]) == 1
        assert len(api_platform_endpoints_msgs[endpoint_arn_2]) == 1
        assert api_contents["region"] == "us-east-1"
        assert api_platform_endpoints_msgs[endpoint_arn][0]["Message"] == json.dumps(
            message_for_topic["APNS"]
        )