
<!-- 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.

{
            RPCHelpMan{"gettxoutproof",
                "\nReturns a hex-encoded proof that \"txid\" was included in a block.\n"
                "\nNOTE: By default this function only works sometimes. This is when there is an\n"
                "unspent output in the utxo for this transaction. To make it always work,\n"
                "you need to maintain a transaction index, using the -txindex command line option or\n"
                "specify the block in which the transaction is included manually (by blockhash).\n",
                {
                    {"txids", RPCArg::Type::ARR, RPCArg::Optional::NO, "The txids to filter",
                        {
                            {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "A transaction hash"},
                        },
                        },
                    {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED_NAMED_ARG, "If specified, looks for txid in the block with this hash"},
                },
                RPCResult{
                    RPCResult::Type::STR, "data", "A string that is a serialized, hex-encoded data for the proof."
                },
                RPCExamples{""},
            }.Check(request);
    std::set<uint256> setTxids;
    uint256 oneTxid;