### 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_
stream_name = f"test-stream-{short_uid()}"
        bucket_name = f"test-bucket-{short_uid()}"
        topic_name = f"test_topic_{short_uid()}"
        trust_policy = {
            "Version": "2012-10-17",
            "Statement": [
                {
                    "Effect": "Allow",
                    "Principal": {"Service": "s3.amazonaws.com"},
                    "Action": "sts:AssumeRole",
                },
                {
                    "Effect": "Allow",
                    "Principal": {"Service": "firehose.amazonaws.com"},
                    "Action": "sts:AssumeRole",
                },
                {
                    "Effect": "Allow",
                    "Principal": {"Service": "sns.amazonaws.com"},
                    "Action": "sts:AssumeRole",
                },
            ],
        }
        role = create_role(RoleName=role_name, AssumeRolePolicyDocument=json.dumps(trust_policy))
        iam_client.attach_role_policy(
            RoleName=role_name,
            PolicyArn="arn:aws:iam::aws:policy/AmazonKinesisFirehoseFullAccess",
        )
        iam_client.attach_role_policy(
            RoleName=role_name, PolicyArn="arn:aws:iam::aws:policy/AmazonS3FullAccess"