[fix][test] Avoid unsafe cleanup between shared-cluster tests

[lhotari]

Motivation

SharedPulsarCluster keeps broker resources and worker threads alive across test classes. FastThreadLocalCleanupListener removes Netty fast-thread-local state between classes, while MockitoCleanupListener reflects into live workers' thread-local maps and performs global inline-mock cleanup. These operations can interfere with resources still owned by the shared cluster.

Global mock cleanup also does not solve ownership: Mockito invocations on a long-lived worker can retain ongoing-stubbing state and its mock graph on that worker. Clearing mocks from a different thread does not remove those references. Tests should avoid invoking mocks on shared workers and explicitly release fixtures they own.

Modifications

• Remove FastThreadLocalCleanupListener and MockitoCleanupListener from the default TestNG listeners and delete the listener implementations. Keep the cleaner utilities for explicitly scoped use.
• Replace shared-worker mocks in dispatcher, reconnection, I/O, TTL, entry-filter, and entry-release tests with real fixtures or small subclasses.
• Add package-private testing helpers for metadata parsing/release and the TTL fallback path, preserving production behavior. Exercise metadata success and failure paths with real entries and buffers.
• Add explicit cleanup for owned mocks and WebSocket annotation fixtures, restore the shared broker interceptor, and close real Netty channels and their event loop.
• Update the multi-topic close test to monitor the scheduled executor provider actually used for retries.

Verifying this change

• Local ./gradlew spotlessCheck checkstyleMain checkstyleTest and ./gradlew quickCheck passed.
• 82 scoped cases across the 13 affected test classes passed with retries disabled: dispatcher permit accounting and read conflation, single-active and classic dispatchers, metadata entry release, reader TTL, subscription and broker stats, multi-topic close, producer reconnection, I/O failures, Netty futures, and WebSocket authorization.
• 12 scoped buildtools cases passed for the listener-removal change.
• Make sure that the change passes the CI checks.

Does this pull request potentially affect one of the following parts:

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment