### 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_
data["SubscribeURL"] = create_subscribe_url(
            external_url, subscriber["TopicArn"], message_context.token
        )
    if message_context.subject:
        data["Subject"] = message_context.subject
    if message_context.message_attributes:
        data["MessageAttributes"] = prepare_message_attributes(message_context.message_attributes)
    return json.dumps(data)
def prepare_message_attributes(
    message_attributes: MessageAttributeMap,
) -> Dict[str, Dict[str, str]]:
    attributes = {}
    if not message_attributes:
        return attributes
    
    
    for attr_name, attr in message_attributes.items():
        data_type = attr["DataType"]
        if data_type.startswith("Binary"):
            
            
            val = base64.b64encode(attr["BinaryValue"]).decode()
        else:
            val = attr.get("StringValue")
        attributes[attr_name] = {
            "Type": data_type,
            "Value": val,
        }
    return attributes
def is_raw_message_delivery(subscriber: SnsSubscription) -> bool: