### 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_
return f"{external_url}/?Action=ConfirmSubscription&TopicArn={topic_arn}&Token={subscription_token}"
def create_unsubscribe_url(external_url, subscription_arn):
    return f"{external_url}/?Action=Unsubscribe&SubscriptionArn={subscription_arn}"
class SubscriptionFilter:
    def check_filter_policy_on_message_attributes(
        self, filter_policy: Dict, message_attributes: Dict
    ):
        for criteria, conditions in filter_policy.items():
            if not self._evaluate_filter_policy_conditions_on_attribute(
                conditions,
                message_attributes.get(criteria),
                field_exists=criteria in message_attributes,
            ):
                return False
        return True
    def check_filter_policy_on_message_body(self, filter_policy: dict, message_body: str):