Support iOS 11 prefersLargeTitles #1643 (#2090)

* Support iOS 11 prefersLargeTitles #1643

* better and more simple version checking and setting

ios/RCCViewController.m

@@ -644,6 +644,12 @@ const NSInteger TRANSPARENT_NAVBAR_TAG = 78264803;
       self.navigationItem.titleView.clipsToBounds = YES;
     }
   }
+  
+  if ([self.navigationController.navigationBar respondsToSelector:@selector(setPrefersLargeTitles:)]) {
+    NSNumber *prefersLargeTitles = self.navigatorStyle[@"prefersLargeTitles"];
+    BOOL prefersLargeTitlesBool = prefersLargeTitles ? [prefersLargeTitles boolValue] : NO;
+    self.navigationController.navigationBar.prefersLargeTitles = prefersLargeTitlesBool;
+  }
 }