### 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_
PlatformApplicationArn=app_arn, Token=short_uid()
        )["EndpointArn"]
        endpoint_arn_2 = sns_client.create_platform_endpoint(
            PlatformApplicationArn=app_arn, Token=short_uid()
        )["EndpointArn"]
        sns_subscription(
            TopicArn=topic_arn,
            Protocol="application",
            Endpoint=endpoint_arn,
        )
        # e
        # h
        message = json.dumps({"APNS": json.dumps({"aps": {"content-available": 1}})})
        message_for_topic = {
            "default": "This is the default message which must be present when publishing a message to a topic.",
            "APNS": json.dumps({"aps": {"content-available": 1}}),
        }
        message_for_topic_string = json.dumps(message_for_topic)
        message_attributes = {
            "AWS.SNS.MOBILE.APNS.TOPIC": {
                "DataType": "String",
                "StringValue": "com.amazon.mobile.messaging.myapp",
            },
            "AWS.SNS.MOBILE.APNS.PUSH_TYPE": {
                "DataType": "String",
                "StringValue": "background",
            },
            "AWS.SNS.MOBILE.APNS.PRIORITY": {
                "DataType": "String",
                "StringValue": "5",