[iOS] Setting title through navigation item doesn't change the tab bar label (#897)

ios/Helpers/RCCTitleViewHelper.m

     self.titleView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin;
     self.titleView.clipsToBounds = YES;
     
-    self.viewController.title = self.title;
+    self.viewController.navigationItem.title = self.title;
     
     if ([self isTitleOnly]) {
         self.viewController.navigationItem.titleView = nil;