[improve][broker] Add logs to getInternalStats
for quickly locate problem when schema ledger is lost
#22233
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Motivation
If schema ledger is lost, when we call the admin interface "topics stats-internal", the server only has the following error log:

However, this log does not clearly indicate which ledger is lost. We don’t even know whether the ledger of topic, cursor or schema is lost. Therefore, it brings challenges to quickly locate the problem.
Modifications
When failed to get ledger metadata for the schema ledger, add logs to quickly locate problem:
log.info("[{}] Failed to get ledger metadata for the schema ledger {}", topic, ledgerId, e);
At this time, we can see the following log, and we can quickly and clearly know that the problem is caused by schema ledger is lost.

Documentation
doc
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