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

{
    int64_t low, high;
    std::tie(low, high) = ParseRange(value);
    if (low < 0) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Range should be greater or equal than 0");
    }
    if ((high >> 31) != 0) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "End of range is too high");
    }
    if (high >= low + 1000000) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Range is too large");
    }
    return {low, high};
}
std::vector<CScript> EvalDescriptorStringOrObject(const UniValue& scanobject, FlatSigningProvider& provider)
{
    std::string desc_str;
    std::pair<int64_t, int64_t> range = {0, 1000};
    if (scanobject.isStr()) {
        desc_str = scanobject.get_str();
    } else if (scanobject.isObject()) {
        UniValue desc_uni = find_value(scanobject, "desc");
        if (desc_uni.isNull()) throw JSONRPCError(RPC_INVALID_PARAMETER, "Descriptor needs to be provided in scan object");
        desc_str = desc_uni.get_str();
        UniValue range_uni = find_value(scanobject, "range");
        if (!range_uni.isNull()) {
            range = ParseDescriptorRange(range_uni);
        }
    } else {