### 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 (
            api_platform_endpoints_msgs[endpoint_arn][0]["MessageAttributes"] == message_attributes
        )
        # E
        msg_with_region = requests.get(msgs_url, params={"region": "eu-west-1"}).json()
        assert len(msg_with_region["platform_endpoint_messages"]) == 0
        assert msg_with_region["region"] == "eu-west-1"
        # E
        api_contents_with_endpoint = requests.get(
            msgs_url, params={"endpointArn": endpoint_arn}
        ).json()
        msgs_with_endpoint = api_contents_with_endpoint["platform_endpoint_messages"]
        assert len(msgs_with_endpoint) == 1
        assert len(msgs_with_endpoint[endpoint_arn]) == 1
        assert api_contents_with_endpoint["region"] == "us-east-1"
        # E
        delete_res = requests.delete(msgs_url, params={"endpointArn": endpoint_arn})
        assert delete_res.status_code == 204
        api_contents_with_endpoint = requests.get(
            msgs_url, params={"endpointArn": endpoint_arn}
        ).json()
        msgs_with_endpoint = api_contents_with_endpoint["platform_endpoint_messages"]
        assert len(msgs_with_endpoint[endpoint_arn]) == 0
        # E
        delete_res = requests.delete(msgs_url, params={"region": "us-east-1"})
        assert delete_res.status_code == 204
        msg_with_region = requests.get(msgs_url, params={"region": "us-east-1"}).json()
        assert not msg_with_region["platform_endpoint_messages"]
    @pytest.mark.only_localstack
    def test_publish_to_platform_endpoint_is_dispatched(