fix typo in member name (#12161)

examples/layers/services/lifecycle.dart

@@ -13,7 +13,7 @@ class LifecycleWatcher extends StatefulWidget {
 
 class _LifecycleWatcherState extends State<LifecycleWatcher>
                              with WidgetsBindingObserver {
-  AppLifecycleState _lastLifecyleState;
+  AppLifecycleState _lastLifecycleState;
 
   @override
   void initState() {
@@ -30,15 +30,15 @@ class _LifecycleWatcherState extends State<LifecycleWatcher>
   @override
   void didChangeAppLifecycleState(AppLifecycleState state) {
     setState(() {
-      _lastLifecyleState = state;
+      _lastLifecycleState = state;
     });
   }
 
   @override
   Widget build(BuildContext context) {
-    if (_lastLifecyleState == null)
+    if (_lastLifecycleState == null)
       return const Text('This widget has not observed any lifecycle changes.');
-    return new Text('The most recent lifecycle state this widget observed was: $_lastLifecyleState.');
+    return new Text('The most recent lifecycle state this widget observed was: $_lastLifecycleState.');
   }
 }