When group insert fails, the error type is not printed in logs.

When group insert fails here, we only print a message and some attributes to the log, without actually printing the error itself. It seems to assume the caller of this method would print the error status, but  unfortunately the caller only checks if the status is OK and ignores it if it's an error instead of printing the error.  This makes it hard to debug issues since we don't know what caused it to fail. We should also exclude `NamespaceNotFound` error from the error log similar to DuplicateKey error, which can also be safely ignore during initial sync.