Can't work with binary data

### Expected Behavior

When producing/consuming from NATS (realtime or not), i expect that i can work with raw bytes without corrupting it.

### Actual Behaviour

It seems the plugin always assume data coming or going from [nats as a string](https://github.com/kestra-io/plugin-nats/blob/main/src/main/java/io/kestra/plugin/nats/core/RealtimeTrigger.java#L177). This will break binary data. For example when sending [binary cloudevent payload](https://github.com/cloudevents/spec/blob/main/cloudevents/bindings/nats-protocol-binding.md#314-example) where the metadata is send through the header so the message payload can be in the form of raw byte for efficientcy

### Steps To Reproduce

- create binary data and record its base64
- publish it to nats
- consume using kestra
- compare the base64

### Environment Information

- Kestra Version:
- Plugin version:
- Operating System (OS / Docker / Kubernetes):
- Java Version (If not docker):

### Example flow

_No response_