[add]: Add important fields to mutual fund type

[brf153]

Earlier I was not getting important mutual fund fields like avg_cost, total_cost, return, etc

I have added these values to Mutual Fund type after which I started getting it

It was present in the nsdl_statement.py

elif current_demat["type"] == "MF":
            if m := re.search(
                NSDL_MF_HOLDINGS_RE,
                line,
                re.DOTALL | re.MULTILINE | re.I,
            ):
                isin, ucc, name, folio, units, avg_cost, total_cost, nav, value, pnl, returns = (
                    m.groups()
                )
                name = re.sub(r"\s+", " ", name).strip()
                name = re.sub(r"[^a-zA-Z0-9_)]+$", "", name).strip()
                current_demat["mutual_funds"].append(
                    {
                        "isin": isin,
                        "ucc": ucc,
                        "name": name,
                        "folio": folio,
                        "balance": units,
                        "avg_cost": avg_cost,
                        "total_cost": total_cost,
                        "nav": nav,
                        "value": value,
                        "pnl": pnl,
                        "return": returns,
                    }
                )

but not in the types