Register IAuthService correctly

Emby.Server.Implementations/ApplicationHost.cs

@@ -842,8 +842,7 @@ namespace Emby.Server.Implementations
             serviceCollection.AddSingleton<IAuthorizationContext>(authContext);
             serviceCollection.AddSingleton<ISessionContext>(new SessionContext(UserManager, authContext, SessionManager));
 
-            AuthService = new AuthService(LoggerFactory.CreateLogger<AuthService>(), authContext, ServerConfigurationManager, SessionManager, NetworkManager);
-            serviceCollection.AddSingleton(AuthService);
+            serviceCollection.AddSingleton<IAuthService, AuthService>();
 
             serviceCollection.AddSingleton<ISubtitleEncoder, MediaBrowser.MediaEncoding.Subtitles.SubtitleEncoder>();