Micrometer Observation Support

### Search before asking

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

### Motivation

I'm a co-maintainer of [Spring Cloud Sleuth](https://github.com/spring-cloud/spring-cloud-sleuth/) and [Micrometer](https://micrometer.io/) projects (together with @shakuzen and @jonatan-ivanov).

[Micrometer Observation](https://micrometer.io/docs/observation) is part of the Micrometer 1.10 release and [Micrometer Tracing](https://micrometer.io/docs/tracing) is a new project. The idea of Micrometer Observation is that you instrument code once but you get multiple benefits out of it - e.g. you can get tracing, metrics, logging or whatever you see fit).

I was curious if there's interest in adding Micrometer Observation support so that except for metrics, spans could be created and tracing context propagation could happen too. Via Micrometer Tracing one can use OpenTelemetry or OpenZipkin Brave Tracer, but with the handler mechanism the possibilities are endless :)

### Solution

If there's such interest we could provide a PR to add support for observability with Micrometer Observation.

### Alternatives

There's none as far as I see

### Anything else?

_No response_

### Are you willing to submit a PR?

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

The issue proposes adding Micrometer Observation support to Apache Pulsar but names no files, tests, or entry points. First review the existing observability and metrics integration, then confirm the intended scope with maintainers. Done should be an agreed implementation with coverage for the supported observation and tracing behavior.

Written by the indexing model from the issue text.