Validate Fii Tickers

FIIs trading on B3 that carry no fii_monthly row — usually a rename.

CVM never refreshes the cadastral ISIN that etl.parsers.cvm_fii.fii_ticker derives the trading code from, so a renamed fund keeps answering under its old code and 404s under the new one until someone pins it in FII_TICKER_OVERRIDES. This lists the funds needing that.

Scoped to BDI 12: Fiagro's 13/14 also carry FI-Infra and FIDC, which have no fii_monthly rows by design and would bury the signal. Subscription rights (KNSC12 and friends) show up here too — they are not funds, so ignore them.