CometBlockResultByNumber returns an error when height=0

At the moment, when calling CometBlockResultByNumber with height=0, an error is returned:

```
failed to fetch block result from Tendermint: failed to fetch block result from Tendermint 0: height must be greater than 0, but got 0
```

This issue happens when trying to filter logs using Ethereum RPC. The correct behaviour would be to use the latest available block.