API to allow access to raw message for TableView

### Search before reporting

- [x] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### Motivation

We use message properties to enable client side message filtering.

However this means we cannot use table view, as it only provides access to the de-serialized message.

### Solution

An API to allow access to raw message object in combination with table view

### Alternatives

Currently using a reader to find the last message ID, then re-reading from the beginning until that message ID.

### Anything else?

_No response_

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

Start by reading the TableView API and tracing where it currently exposes only the deserialized message. Compare that path with the raw message access available to readers, then define and test the TableView API behavior needed to expose message properties while preserving existing consumers.

Written by the indexing model from the issue text.