Change vc to self.screenView.controller

ios/RNSScreenStackHeaderConfig.mm

@@ -150,7 +150,7 @@ - (void)updateViewControllerIfNeeded
     // As the header might have change in `updateViewController` we need to ensure that header height
     // returned by the `onHeaderHeightChange` event is correct.
     if ([vc isKindOfClass:[RNSScreen class]]) {
-      [(RNSScreen *)vc calculateAndNotifyHeaderHeightChangeIsModal:NO];
+      [(RNSScreen *)self.screenView.controller calculateAndNotifyHeaderHeightChangeIsModal:NO];
     }
   }
 }