fix(firebase_messaging): ensure silent foreground messages for iOS ar…

…e called via event channel. (#8635)

* fix(messaging): silent foreground messages for iOS

* fix(messaging): single silent foreground message for iOS

packages/firebase_messaging/firebase_messaging/ios/Classes/FLTFirebaseMessagingPlugin.m

@@ -422,6 +422,7 @@ - (void)application:(NSApplication *)application
 #endif
 
 #if !TARGET_OS_OSX
+// Called for silent notifications in the foreground & background
 - (BOOL)application:(UIApplication *)application
     didReceiveRemoteNotification:(NSDictionary *)userInfo
           fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler {
@@ -431,12 +432,10 @@ - (BOOL)application:(UIApplication *)application
     return YES;
   }
 #endif
-
+  NSDictionary *notificationDict =
+      [FLTFirebaseMessagingPlugin remoteMessageUserInfoToDict:userInfo];
   // Only handle notifications from FCM.
   if (userInfo[@"gcm.message_id"]) {
-    NSDictionary *notificationDict =
-        [FLTFirebaseMessagingPlugin remoteMessageUserInfoToDict:userInfo];
-
     if ([UIApplication sharedApplication].applicationState == UIApplicationStateBackground) {
       __block BOOL completed = NO;
 
@@ -485,6 +484,11 @@ - (BOOL)application:(UIApplication *)application
                         }
                       }];
     } else {
+      // If "alert" (i.e. notification) is present, this will be called by the other
+      // "Messaging#onMessage" channel handler
+      if (notificationDict[@"aps"] != nil && notificationDict[@"aps"][@"alert"] == nil) {
+        [_channel invokeMethod:@"Messaging#onMessage" arguments:notificationDict];
+      }
       completionHandler(UIBackgroundFetchResultNoData);
     }