Delay Notification Opened Check in Objective-C Plugin

• Delays the check to see if a notification was opened after init. This is intended to prevent situations where the developer synchronously adds the NotificationOpened handler *after* calling OneSignal.init().
• Since the SDK is checking to see if a notification was opened on cold start AND synchronously calls the handler during the init() call, this would result in apps that add the observers after calling init() not getting cold-start notification opened events.
• Switches to passing in false as the default autoPrompt setting on the first call to init() (which happens before the Flutter SDK initializes and the developer calls init() with their real app ID).
• Implements the kOSSettingsKeyInOmitNoAppIdLogging setting. Since the SDK calls init() twice, the first time it passes in nil as the app ID (this happens before the Flutter channel is set up). To prevent the SDK from logging a "no appID" error, we pass in the kOSSettingsKeyInOmitNoAppIdLogging setting

Author: Nightsd01

ios/Classes/OneSignalPlugin.m

@@ -71,11 +71,14 @@ + (instancetype)sharedInstance
 #pragma mark FlutterPlugin
 + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
 
+    // Wrapper SDK's call init with no app ID early on in the
+    // app lifecycle. The developer will call init() later on
+    // from the Flutter plugin channel.
     [OneSignal initWithLaunchOptions:nil appId:nil handleNotificationAction:^(OSNotificationOpenedResult *result) {
         @synchronized (OneSignalPlugin.sharedInstance.coldStartOpenResult) {
             OneSignalPlugin.sharedInstance.coldStartOpenResult = result;
         }
-    }];
+    } settings:@{kOSSettingsKeyAutoPrompt : @false, @"kOSSettingsKeyInOmitNoAppIdLogging" : @true}];
 
     OneSignalPlugin.sharedInstance.channel = [FlutterMethodChannel
                                      methodChannelWithName:@"OneSignal"
@@ -141,11 +144,18 @@ - (void)initOneSignal:(FlutterMethodCall *)call withResult:(FlutterResult)result
         [self addObservers];
     }
 
-    @synchronized(self.coldStartOpenResult) {
-        if (self.coldStartOpenResult) {
-            [self handleNotificationOpened:self.coldStartOpenResult];
+    //since the developer may add the NotificationOpened handler
+    //after they call OneSignal.init(), we delay this check to
+    //make sure the app has had enough time to reasonably add
+    //the NotificationOpened handler.
+    
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+        @synchronized(self.coldStartOpenResult) {
+            if (self.coldStartOpenResult) {
+                [self handleNotificationOpened:self.coldStartOpenResult];
+            }
         }
-    }
+    });
 
     result(@[]);
 }