Fix warnings in ChannelManager

Emby.Server.Implementations/Channels/ChannelManager.cs

@@ -10,8 +10,8 @@ using System.Threading;
 using System.Threading.Tasks;
 using Jellyfin.Data.Entities;
 using Jellyfin.Data.Enums;
-using MediaBrowser.Common.Extensions;
 using Jellyfin.Extensions.Json;
+using MediaBrowser.Common.Extensions;
 using MediaBrowser.Common.Progress;
 using MediaBrowser.Controller.Channels;
 using MediaBrowser.Controller.Configuration;