
<!-- 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.

RPCExamples{
                    HelpExampleCli("getrawtransaction", "\"mytxid\"")
            + HelpExampleCli("getrawtransaction", "\"mytxid\" true")
            + HelpExampleRpc("getrawtransaction", "\"mytxid\", true")
            + HelpExampleCli("getrawtransaction", "\"mytxid\" false \"myblockhash\"")
            + HelpExampleCli("getrawtransaction", "\"mytxid\" true \"myblockhash\"")
                },
    }.Check(request);
    bool in_active_chain = true;
    uint256 hash = ParseHashV(request.params[0], "parameter 1");
    CBlockIndex* blockindex = nullptr;
    if (hash == Params().GenesisBlock().hashMerkleRoot) {
        
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "The genesis block coinbase is not considered an ordinary transaction and cannot be retrieved");
    }
    
    bool fVerbose = false;
    if (!request.params[1].isNull()) {
        fVerbose = request.params[1].isNum() ? (request.params[1].get_int() != 0) : request.params[1].get_bool();
    }
    if (!request.params[2].isNull()) {
        LOCK(cs_main);
        uint256 blockhash = ParseHashV(request.params[2], "parameter 3");
        blockindex = LookupBlockIndex(blockhash);
        if (!blockindex) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block hash not found");
        }
        in_active_chain = ::ChainActive().Contains(blockindex);
    }
    bool f_txindex_ready = false;