### 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_
response = sns_client.publish(PhoneNumber="+33000000000", Message="This is a SMS")
        assert "MessageId" in response
        assert response["ResponseMetadata"]["HTTPStatusCode"] == 200
    @pytest.mark.aws_validated
    def test_publish_non_existent_target(self, sns_client, sns_create_topic, snapshot):
        topic_arn = sns_create_topic()["TopicArn"]
        account_id = parse_arn(topic_arn)["account"]
        with pytest.raises(ClientError) as ex:
            sns_client.publish(
                TargetArn=f"arn:aws:sns:us-east-1:{account_id}:endpoint/APNS/abcdef/0f7d5971-aa8b-4bd5-b585-0826e9f93a66",
                Message="This is a push notification",
            )
        snapshot.match("non-existent-endpoint", ex.value.response)
    @pytest.mark.aws_validated
    def test_tags(self, sns_client, sns_create_topic, snapshot):
        topic_arn = sns_create_topic()["TopicArn"]
        with pytest.raises(ClientError) as exc:
            sns_client.tag_resource(
                ResourceArn=topic_arn,
                Tags=[
                    {"Key": "k1", "Value": "v1"},
                    {"Key": "k2", "Value": "v2"},
                    {"Key": "k2", "Value": "v2"},
                ],