[fix][broker] Forward topic policy updates after init failures

[Denovo1998]

Motivation

PR #26044 made topic policy listeners buffer live updates until the initial topic-policy load completes, so a topic can start with the latest policy state. However, PersistentTopic.initialize() logs and continues when that initial load fails. In that path, the listener wrapper stays uninitialized, so later live topic-policy updates are buffered forever instead of being delivered to the topic.

Modifications

• Complete the TopicPolicyListenerWrapper with empty loaded policies when the initial global/local topic-policy lookup fails.
• Preserve the original failed future so topic loading keeps the existing log-and-continue behavior.
• Keep buffered live updates authoritative if an update arrives before the failure handling runs.
• Add a regression test for initial policy load failure followed by a live local topic-policy update.

Verifying this change

• Make sure that the change passes the CI checks.

• gradlew :pulsar-broker:test --tests org.apache.pulsar.broker.service.persistent.PersistentTopicTest.testTopicPolicyListenerForwardsLiveUpdatesAfterInitialLoadFailure --rerun-tasks

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

If the box was checked, please highlight the changes

• 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