I have 2 legacy wallets and on both if I run `upgradewallet` it will cause bitcoin core to crash. This should just return me an error string

Currenl result from `getwalletinfo`:
```
{
  "walletname": "Wallet",
  "walletversion": 169900,
  "format": "bdb",
  "balance": 0.00000000,
  "unconfirmed_balance": 0.00000000,
  "immature_balance": 0.00000000,
  "txcount": 80,
  "keypoololdest": 1613078825,
  "keypoolsize": 941,
  "keypoolsize_hd_internal": 941,
  "paytxfee": 0.00000000,
  "private_keys_enabled": false,
  "avoid_reuse": true,
  "scanning": false,
  "descriptors": false
}
```
{
    return uint256::ONE;
}
/**
 * Update wallet first key creation time. This should be called whenever keys
 * are added to the wallet, with the oldest key creation time.
 */
void LegacyScriptPubKeyMan::UpdateTimeFirstKey(int64_t nCreateTime)
{
    AssertLockHeld(cs_KeyStore);
    if (nCreateTime <= 1) {
        
        
        nTimeFirstKey = 1;
    } else if (!nTimeFirstKey || nCreateTime < nTimeFirstKey) {
        nTimeFirstKey = nCreateTime;
    }
}
bool LegacyScriptPubKeyMan::LoadKey(const CKey& key, const CPubKey &pubkey)
{
    return AddKeyPubKeyInner(key, pubkey);
}
bool LegacyScriptPubKeyMan::AddKeyPubKey(const CKey& secret, const CPubKey &pubkey)