Support listing and exporting voice channels

Closes #874

DiscordChatExporter.Cli/Commands/GetDirectMessageChannelsCommand.cs

@@ -17,7 +17,6 @@ public class GetDirectMessageChannelsCommand : TokenCommandBase
         var cancellationToken = console.RegisterCancellationHandler();
 
         var channels = (await Discord.GetGuildChannelsAsync(Guild.DirectMessages.Id, cancellationToken))
-            .Where(c => c.Kind.IsText())
             .OrderByDescending(c => c.LastMessageId)
             .ThenBy(c => c.Name)
             .ToArray();