[feature request] C++ and Python support negative acknowledgment backoff

### Search before asking

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

### Motivation

[PIP-106](https://github.com/apache/pulsar/wiki/PIP-106%3A-Negative-acknowledgment-backoff)

### Solution

Refer java client: https://github.com/apache/pulsar/pull/12566

### Alternatives

_No response_

### Anything else?

If the `redeliveryCount` is greater than the DLQ configuration, it needs to be sent to the DLQ.

### Are you willing to submit a PR?

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

Start by reading PIP-106 and the referenced Java client pull request 12566 to understand the negative-acknowledgment backoff behavior. Trace the corresponding C++ and Python client paths, then verify that redeliveryCount values beyond the DLQ configuration are sent to the DLQ and that both clients match the Java behavior.

Written by the indexing model from the issue text.