[fix][test] Using another thread instead of io-thread for bookie

[zymap]

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Master Issue: #17520

Motivation

In the bookkeeper, the request processor should use a dedicated thread pool, not the io thread pool to process the request. Using io thread pool may cause some unexpected behaviors, such as a deadlock or something else. In the production, it doesn't make sense that use io thread pool to handle everything. So change the working thread to 1 to fix the problem.

Modifications

• change AddWorkerThreads, ReadWorkerThreads, and HighPriorityWorkerThreads to 1

Verifying this change

• Make sure that the change passes the CI checks.

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This change is a trivial rework / code cleanup without any test coverage.

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This change is already covered by existing tests, such as (please describe tests).

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This change added tests and can be verified as follows:

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• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

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

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• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API: (yes / no)
• The schema: (yes / no / don't know)
• The default values of configurations: (yes / no)
• The wire protocol: (yes / no)
• The rest endpoints: (yes / no)
• The admin cli options: (yes / no)
• Anything that affects deployment: (yes / no / don't know)

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[zymap]

Discussed with @codelipenghui and @hangc0276. We think the error happened caused by bookkeeper fix, and it doesn't impact the pulsar too much, so it is unnecessary to change the pulsar to tolerate that case.