### 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_
with pytest.raises(ClientError) as e:
                sns_client.publish(
                    TopicArn=topic_arn,
                    Message="test message",
                    MessageAttributes=msg_attrs,
                )
            snapshot.match(error_type, e.value.response)
        with pytest.raises(ClientError) as e:
            sns_client.publish_batch(
                TopicArn=topic_arn,
                PublishBatchRequestEntries=[
                    {
                        "Id": "1",
                        "Message": "test-batch",
                        "MessageAttributes": wrong_message_attributes["missing_string_attr"],
                    },
                    {
                        "Id": "2",
                        "Message": "test-batch",
                        "MessageAttributes": wrong_message_attributes["str_attr_binary_value"],
                    },
                    {
                        "Id": "3",
                        "Message": "valid-batch",
                    },
                ],
            )
        snapshot.match("batch-exception", e.value.response)
    @pytest.mark.only_localstack
    def test_publish_to_platform_endpoint_can_retrospect(