External inputs are currently only supported for initial transaction creation functions. Extend `solving_data` arguments as necessary to support fee bumping wallet transactions with non-wallet inputs.

https://github.com/bitcoin/bitcoin/pull/17211#issuecomment-897653994
return feebumper::Result::INVALID_PARAMETER;
    }
    {
        if (wallet.chain().hasDescendantsInMempool(wtx.GetHash())) {
            errors.push_back(Untranslated("Transaction has descendants in the mempool"));
            return feebumper::Result::INVALID_PARAMETER;
        }
    }
    if (wallet.GetTxDepthInMainChain(wtx) != 0) {
        errors.push_back(Untranslated("Transaction has been mined, or is conflicted with a mined transaction"));
        return feebumper::Result::WALLET_ERROR;
    }
    if (!SignalsOptInRBF(*wtx.tx)) {
        errors.push_back(Untranslated("Transaction is not BIP 125 replaceable"));
        return feebumper::Result::WALLET_ERROR;
    }
    if (wtx.mapValue.count("replaced_by_txid")) {
        errors.push_back(strprintf(Untranslated("Cannot bump transaction %s which was already bumped by transaction %s"), wtx.GetHash().ToString(), wtx.mapValue.at("replaced_by_txid")));
        return feebumper::Result::WALLET_ERROR;
    }
    
    
    isminefilter filter = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) ? ISMINE_WATCH_ONLY : ISMINE_SPENDABLE;
    if (!AllInputsMine(wallet, *wtx.tx, filter)) {
        errors.push_back(Untranslated("Transaction contains inputs that don't belong to this wallet"));
        return feebumper::Result::WALLET_ERROR;
    }
    return feebumper::Result::OK;
}
static feebumper::Result CheckFeeRate(const CWallet& wallet, const CWalletTx& wtx, const CFeeRate& newFeerate, const int64_t maxTxSize, std::vector<bilingual_str>& errors)