Steps to reproduce on regtest:

```
converttopsbt 02000000000101ab73dba46508bacdb49a988ddd74bc9d39c9cb7e057af060ca8c6b6861e28e3c0300000000feffffff02b828d0b20000000017a914d1954862afd728fbb055149002958e1d1b9e1f0b8700ca9a3b0000000017a91442170ccb3441cff1723af9afab6f2553103e1d578702473044022077380c6e16496d9905aef120694c329be51522847cb5d53fa74b94698c95678d02202d32c46e0e17420a83dee830fefda7d40529182f5d82be47c2b49a7b83214ab50121026d483d6628dcc3ef6e3ab9ed4937c452c263c7e0ac80eb4be97426d5da8f640500000000
```
or 
```
converttopsbt 02000000000101ab73dba46508bacdb49a988ddd74bc9d39c9cb7e057af060ca8c6b6861e28e3c0300000000feffffff02b828d0b20000000017a914d1954862afd728fbb055149002958e1d1b9e1f0b8700ca9a3b0000000017a91442170ccb3441cff1723af9afab6f2553103e1d578702473044022077380c6e16496d9905aef120694c329be51522847cb5d53fa74b94698c95678d02202d32c46e0e17420a83dee830fefda7d40529182f5d82be47c2b49a7b83214ab50121026d483d6628dcc3ef6e3ab9ed4937c452c263c7e0ac80eb4be97426d5da8f640500000000 false
```

Further reading: #13738
throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
    }
    bool extract = request.params[1].isNull() || (!request.params[1].isNull() && request.params[1].get_bool());
    CMutableTransaction mtx;
    bool complete = FinalizeAndExtractPSBT(psbtx, mtx);
    UniValue result(UniValue::VOBJ);
    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
    std::string result_str;
    if (complete && extract) {
        ssTx << mtx;
        result_str = HexStr(ssTx.str());
        result.pushKV("hex", result_str);
    } else {
        ssTx << psbtx;
        result_str = EncodeBase64(ssTx.str());
        result.pushKV("psbt", result_str);
    }
    result.pushKV("complete", complete);
    return result;
}
UniValue createpsbt(const JSONRPCRequest& request)
{
    if (request.fHelp || request.params.size() < 2 || request.params.size() > 4)
        throw std::runtime_error(
            RPCHelpMan{"createpsbt",
                "\nCreates a transaction in the Partially Signed Transaction format.\n"
                "Implements the Creator role.\n",
                {
                    {"inputs", RPCArg::Type::ARR, RPCArg::Optional::NO, "A json array of json objects",
                        {