oops, forgot to update modifyasync

src/Discord.Net.Rest/Entities/Channels/ForumHelper.cs

@@ -56,7 +56,8 @@ internal static class ForumHelper
                         emoji.Name : Optional<string>.Unspecified
                 }
                 : Optional<ModifyForumReactionEmojiParams>.Unspecified,
-            DefaultSortOrder = args.DefaultSortOrder
+            DefaultSortOrder = args.DefaultSortOrder,
+            DefaultLayout = args.DefaultLayout,
         };
         return await client.ApiClient.ModifyGuildChannelAsync(channel.Id, apiArgs, options).ConfigureAwait(false);
     }