Use better way to initialize task manager listener and timers

lib/auth.dart

@@ -89,6 +89,7 @@ class AuthInfo {
             "Logged in as ${u.username} (${u.id}). isAdmin: ${u.isAdmin}. permissions: ${u.permissions}");
         await checkSessionInfo();
         if (canManageTasks == true) {
+          if (!tasks.inited) tasks.init();
           await tasks.connect();
         }
       } else if (re.status == 401 || re.status == 1 || re.status == 404) {

lib/main.dart

@@ -299,7 +299,6 @@ class _MainApp extends State<MainApp> with WidgetsBindingObserver {
       _lifecycleState = WidgetsBinding.instance.lifecycleState;
       listener.tryEmit("lifecycle", _lifecycleState);
     }
-    tasks.init();
   }
 
   @override

lib/task.dart

@@ -22,6 +22,8 @@ class TaskManager {
   List<int> peddingGids = [];
   List<String> peddingTokens = [];
   late Timer _pingTimer;
+  bool _inited = false;
+  bool get inited => _inited;
   void clear() {
     tasks.clear();
     _channel?.stream.drain();
@@ -233,6 +235,7 @@ class TaskManager {
   }
 
   void init() {
+    _inited = true;
     listener.on("lifecycle", _onLifeCycleChanged);
     _pingTimer = Timer.periodic(const Duration(seconds: 30), (timer) {
       try {