
<!-- Describe the issue -->
Following commit 46004790588c24174a0bec49b540d158ce163ffd (@achow101), `decodepsbt` overstates the fee, apparently including both the `witness_utxo` and `non_witness_utxo` amounts in the inputs.

**Expected behavior**

The decoded fee should be the sum of the inputs, minus the sum of the outputs.

**Actual behavior**

The decoded fee is exactly twice the amount of the inputs, minus the sum of the outputs.

**To reproduce**

Build any PSBT using `createpsbt`, `walletprocesspsbt`, then decode it with `decodepsbt`. See the `fee` field in the JSON.

**System information**

I compiled myself from 5550fa5983ea59e7ccef6540b7ec49a1770fb3ca on Whonix 14.

Then I did `git revert 46004790588c24174a0bec49b540d158ce163ffd ` and the problem went away.

have_all_utxos = false;
            }
            UniValue o(UniValue::VOBJ);
            ScriptToUniv(txout.scriptPubKey, o, true);
            out.pushKV("scriptPubKey", o);
            in.pushKV("witness_utxo", out);
            have_a_utxo = true;
        }
        if (input.non_witness_utxo) {
            UniValue non_wit(UniValue::VOBJ);
            TxToUniv(*input.non_witness_utxo, uint256(), non_wit, false);
            in.pushKV("non_witness_utxo", non_wit);
            CAmount utxo_val = input.non_witness_utxo->vout[psbtx.tx->vin[i].prevout.n].nValue;
            if (MoneyRange(utxo_val) && MoneyRange(total_in + utxo_val)) {
                total_in += utxo_val;
            } else {
                
                have_all_utxos = false;
            }
            have_a_utxo = true;
        }
        if (!have_a_utxo) {
            have_all_utxos = false;
        }
        
        if (!input.partial_sigs.empty()) {
            UniValue partial_sigs(UniValue::VOBJ);
            for (const auto& sig : input.partial_sigs) {
                partial_sigs.pushKV(HexStr(sig.second.first), HexStr(sig.second.second));
            }