Simplify HostApplicationLifetime instantiation

Removed the `cancellationTokenSource` parameter from the instantiation of `HostApplicationLifetime` when adding it as a singleton service to the `Services` collection. This change decouples `HostApplicationLifetime` from `CancellationTokenSource`, potentially simplifying lifecycle management and addressing specific design requirements.

Author: bvdcode

Sources/TelegramBot/Builders/BotBuilder.cs

@@ -141,7 +141,7 @@ public IBot Build()
                 Services.AddSingleton<IKeyValueProvider, InMemoryKeyValueProvider>();
             }
             CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
-            Services.AddSingleton<IHostApplicationLifetime, HostApplicationLifetime>(x => new HostApplicationLifetime(cancellationTokenSource));
+            Services.AddSingleton<IHostApplicationLifetime, HostApplicationLifetime>(x => new HostApplicationLifetime());
             return new BotApp(client, Services.BuildServiceProvider(), cancellationTokenSource);
         }
     }