values smaller than 0.001 sat/B can't be represented by CFeeRate, but they are not rejected.

```
./src/bitcoin-cli -named sendtoaddress address=bcrt1qwkmhqum095zau5rf2velq55cq938vrd7uw8m4r amount=1.23 fee_rate=0.0009

error code: -6
error message:
Fee rate (0.000 sat/vB) is lower than the minimum fee rate setting (1.000 sat/vB)
```

```
./src/bitcoin-cli -named sendtoaddress address=bcrt1qwkmhqum095zau5rf2velq55cq938vrd7uw8m4r amount=1.23 fee_rate=0.000000000009

error code: -3
error message:
Invalid amount

"\"orphan\"                Orphaned coinbase transactions received."},
                            {RPCResult::Type::STR_AMOUNT, "amount", "The amount in " + CURRENCY_UNIT + ". This is negative for the 'send' category, and is positive\n"
                                "for all other categories"},
                            {RPCResult::Type::STR, "label", "A comment for the address/transaction, if any"},
                            {RPCResult::Type::NUM, "vout", "the vout value"},
                            {RPCResult::Type::STR_AMOUNT, "fee", "The amount of the fee in " + CURRENCY_UNIT + ". This is negative and only available for the\n"
                                 "'send' category of transactions."},
                        },
                        TransactionDescriptionString()),
                        {
                            {RPCResult::Type::BOOL, "abandoned", "'true' if the transaction has been abandoned (inputs are respendable). Only available for the \n"
                                 "'send' category of transactions."},
                        })},
                    }
                },
                RPCExamples{
            "\nList the most recent 10 transactions in the systems\n"
            + HelpExampleCli("listtransactions", "") +
            "\nList transactions 100 to 120\n"
            + HelpExampleCli("listtransactions", "\"*\" 20 100") +
            "\nAs a JSON-RPC call\n"
            + HelpExampleRpc("listtransactions", "\"*\", 20, 100")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    std::shared_ptr<CWallet> const pwallet = GetWalletForJSONRPCRequest(request);
    if (!pwallet) return NullUniValue;
    
    
    pwallet->BlockUntilSyncedToCurrentChain();