
<!-- 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.

{RPCResult::Type::NUM, "vout", "The output number"},
                                {RPCResult::Type::OBJ, "scriptSig", "The script",
                                {
                                    {RPCResult::Type::STR, "asm", "asm"},
                                    {RPCResult::Type::STR_HEX, "hex", "hex"},
                                }},
                                {RPCResult::Type::ARR, "txinwitness", "",
                                {
                                    {RPCResult::Type::STR_HEX, "hex", "hex-encoded witness data (if any)"},
                                }},
                                {RPCResult::Type::NUM, "sequence", "The script sequence number"},
                            }},
                        }},
                        {RPCResult::Type::ARR, "vout", "",
                        {
                            {RPCResult::Type::OBJ, "", "",
                            {
                                {RPCResult::Type::NUM, "value", "The value in " + CURRENCY_UNIT},
                                {RPCResult::Type::NUM, "n", "index"},
                                {RPCResult::Type::OBJ, "scriptPubKey", "",
                                {
                                    {RPCResult::Type::STR, "asm", "the asm"},
                                    {RPCResult::Type::STR_HEX, "hex", "the hex"},
                                    {RPCResult::Type::NUM, "reqSigs", "The required sigs"},
                                    {RPCResult::Type::STR, "type", "The type, eg 'pubkeyhash'"},
                                    {RPCResult::Type::ARR, "addresses", "",
                                    {
                                        {RPCResult::Type::STR, "address", "bitcoin address"},
                                    }},
                                }},