[fix][client] The input parameters for PulsarPullConsumerImpl have been changed from PulsarAdmin parameters to Supplier format, requiring dynamic updates.

[StevenLuMT]

Motivation

PulsarPullConsumerImpl currently accepts a fixed PulsarAdmin instance. This is inconsistent with the existing Supplier<PulsarClient> design and prevents the pull consumer from obtaining an updated PulsarAdmin instance when the underlying client/admin needs to be refreshed dynamically.

Modifications

1. Replace the PulsarAdmin constructor parameter in PulsarPullConsumerImpl with Supplier<PulsarAdmin>.
2. Add getPulsarAdmin() to obtain and validate the current PulsarAdmin instance when it is needed.
3. Update all PulsarAdmin usages, including:
   • partition metadata initialization;
   • offset-to-message-id cache initialization;
   • timestamp-based offset lookup;
   • consume stats query.
4. Update existing PulsarPullConsumerTest cases to pass PulsarAdmin through a supplier.

Verifying this change

This change updates existing tests to use the new constructor signature. The existing pull consumer test coverage continues to verify:

• pull consumer initialization;
• offset lookup by timestamp;
• consume stats query.