<!-- Describe what has changed in this PR -->
Reduce log level of shard finalizer warning.
<!-- Tell your future self why have you made these changes -->
It's being logged more often than expected.
The reason why it's logging excessively isn't clear, so more
investigation is needed. But this will mitigate the symptom for now.
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test? Checked in staging env? -->
Debug is not logged in production.
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change to production? -->
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stated in `docs/`? If significant
new behavior is added, have you described that in `docs/`? -->
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be sent to the broader community? (Yes/No) -->
Yes.
