Consider including Code in FtpReply Message

[jnyrup]

FluentFTP Version: 33.1.3

I hit a case in our logs yesterday where it seems the information included in the FtpCommandException could be improved. From how I read the code, it indicates to me that the the FtpReply was unsuccessful, but InfoMessages was insufficient to generate a non-empty ErrorMessage. In that case you could consider a fallback where the Code property is included in the ErrorMessage. I don't know enough about the correlation between InfoMessages and Code to tell if it would be duplicate information, if Code was always included in the ErrorMessage.

Logs :

FluentFTP.FtpCommandException
   at async Task FluentFTP.FtpClient.SetDataTypeNoLockAsync(FtpDataType type, CancellationToken token)
   at async Task<List<string>> FluentFTP.FtpClient.GetListingInternalAsync(string listcmd, FtpListOption options, bool retry, CancellationToken token)
   at async Task<FtpListItem[]> FluentFTP.FtpClient.GetListingAsync(string path, FtpListOption options, CancellationToken token)