
<!-- 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::STR_HEX, "hex", "hex-encoded witness data (if any)"},
                                     }},
                                 }},
                             }},
                             {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", "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"},
                                         }},
                                     }},
                                 }},
                             }},
                             {RPCResult::Type::STR_HEX, "blockhash", "the block hash"},
                             {RPCResult::Type::NUM, "confirmations", "The confirmations"},
                             {RPCResult::Type::NUM_TIME, "blocktime", "The block time expressed in " + UNIX_EPOCH_TIME},
                             {RPCResult::Type::NUM, "time", "Same as \"blocktime\""},
                        }
                    },
                },