kafka: fix exception handle for delete topic and read latency tracking

[YangKian]

PR Description

Type of change

• Bug fix

Summary of the change and which issue is fixed

Main changes:

• fix incorrect errorCode:
  If two clients, a and b, perform the following operations concurrently: listTopic >>= deleteTopic, then in the delete handler, even if S.doesStreamExist returns true, the subsequent deletion may still throw a NOTFOUND exception. In this case, this exception would be incorrectly mapped to UNKNOWN_SERVER_ERROR, rather than UNKNOWN_TOPIC_OR_PARTITION.
• fix read latency tracking for consume handler

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Checklist

• I have run format.sh under script
• I have commented my code, particularly in hard-to-understand areas
• New and existing unit tests pass locally with my changes