Update remote_notification.dart to fix typo in docs

fix typo of `construted` to `constructed`

Author: timmaffett

packages/firebase_messaging/firebase_messaging_platform_interface/lib/src/remote_notification.dart

@@ -7,7 +7,7 @@ import 'package:firebase_messaging_platform_interface/firebase_messaging_platfor
 
 import 'utils.dart';
 
-/// A class representing a notification which has been construted and sent to the
+/// A class representing a notification which has been constructed and sent to the
 /// device via FCM.
 ///
 /// This class can be accessed via a [RemoteMessage.notification].