
<!-- 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.

"       \"ALL\"\n"
            "       \"NONE\"\n"
            "       \"SINGLE\"\n"
            "       \"ALL|ANYONECANPAY\"\n"
            "       \"NONE|ANYONECANPAY\"\n"
            "       \"SINGLE|ANYONECANPAY\"\n"
                    },
                },
                RPCResult{
                    RPCResult::Type::OBJ, "", "",
                    {
                        {RPCResult::Type::STR_HEX, "hex", "The hex-encoded raw transaction with signature(s)"},
                        {RPCResult::Type::BOOL, "complete", "If the transaction has a complete set of signatures"},
                        {RPCResult::Type::ARR, "errors", "Script verification errors (if there are any)",
                        {
                            {RPCResult::Type::OBJ, "", "",
                            {
                                {RPCResult::Type::STR_HEX, "txid", "The hash of the referenced, previous transaction"},
                                {RPCResult::Type::NUM, "vout", "The index of the output to spent and used as input"},
                                {RPCResult::Type::STR_HEX, "scriptSig", "The hex-encoded signature script"},
                                {RPCResult::Type::NUM, "sequence", "Script sequence number"},
                                {RPCResult::Type::STR, "error", "Verification or signing error related to the input"},
                            }},
                        }},
                    }
                },
                RPCExamples{
                    HelpExampleCli("signrawtransactionwithkey", "\"myhex\" \"[\\\"key1\\\",\\\"key2\\\"]\"")
            + HelpExampleRpc("signrawtransactionwithkey", "\"myhex\", \"[\\\"key1\\\",\\\"key2\\\"]\"")
                },