issue: #43858
Fix the issue introduced in PR #43992 where deactivating the balance
checker incorrectly stops stopping balance operations.
Changes:
- Move IsActive() check after stopping balance logic
- Only skip normal balance when checker is inactive
- Allow stopping balance to proceed regardless of checker state
This ensures stopping balance can execute even when the balance checker
is deactivated.
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Signed-off-by: Wei Liu <wei.liu@zilliz.com>