`ScanForWalletTransactions()` has the following comment about its return value:

```
 * Returns null if scan was successful. Otherwise, if a complete rescan was not
 * possible (due to pruning or corruption), returns pointer to the most recent
 * block that could not be scanned.
```

This is not strictly true. If `abortrescan` is called, then `ScanForWalletTransactions()` will return `nullptr`, even though the scan wasn't successful to the tip.

This in turn causes a minor bug in `importmulti`, where the call doesn't return the correct error and warning about potentially not finding transactions if `abortrescan` was called.

I think the correct fix is for `ScanForWalletTransactions()` to inform the caller that the rescan was aborted.
"or (for backwards compatibility) the name of an existing data file in -walletdir (%s)",
              location.GetName(), GetWalletDir());
        return false;
    }
    
    for (auto wallet : GetWallets()) {
        if (wallet->GetLocation().GetPath() == wallet_path) {
            error_string = strprintf("Error loading wallet %s. Duplicate -wallet filename specified.", location.GetName());
            return false;
        }
    }
    try {
        if (!WalletBatch::VerifyEnvironment(wallet_path, error_string)) {
            return false;
        }
    } catch (const fs::filesystem_error& e) {
        error_string = strprintf("Error loading wallet %s. %s", location.GetName(), fsbridge::get_filesystem_error_message(e));
        return false;
    }
    if (salvage_wallet) {
        
        CWallet dummyWallet(chain, WalletLocation(), WalletDatabase::CreateDummy());
        std::string backup_filename;
        if (!WalletBatch::Recover(wallet_path, (void *)&dummyWallet, WalletBatch::RecoverKeysOnlyFilter, backup_filename)) {
            return false;
        }
    }
    return WalletBatch::VerifyDatabaseFile(wallet_path, warning_string, error_string);
}
std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(interfaces::Chain& chain, const WalletLocation& location, uint64_t wallet_creation_flags)