[RN] fix duplicate observe

React/Modules/RCTAppState.m

@@ -48,18 +48,17 @@ RCT_EXPORT_MODULE()
     for (NSString *name in @[UIApplicationDidBecomeActiveNotification,
                              UIApplicationDidEnterBackgroundNotification,
                              UIApplicationDidFinishLaunchingNotification]) {
-
       [[NSNotificationCenter defaultCenter] addObserver:self
                                                selector:@selector(handleAppStateDidChange)
                                                    name:name
                                                  object:nil];
+    }
 
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(handleMemoryWarning)
                                                  name:UIApplicationDidReceiveMemoryWarningNotification
                                                object:nil];
   }
-  }
   return self;
 }