Fix reatain cycle RCTPullToRefreshViewComponentView <-> RCTScrollView…

…ComponentView

Summary:
Changelog: [iOS][Fixed] - `_scrollViewComponentView` is set to `RCTPullToRefreshViewComponentView's` superview:
```
_scrollViewComponentView = [RCTScrollViewComponentView findScrollViewComponentViewForView:self];
```
It should be safe to make it weak.

Reviewed By: javache

Differential Revision: D36998626

fbshipit-source-id: 2130b743d181e15986cb68636d60507a986968e1

React/Fabric/Mounting/ComponentViews/ScrollView/RCTPullToRefreshViewComponentView.mm

@@ -25,7 +25,7 @@ @interface RCTPullToRefreshViewComponentView () <RCTPullToRefreshViewViewProtoco
 
 @implementation RCTPullToRefreshViewComponentView {
   UIRefreshControl *_refreshControl;
-  RCTScrollViewComponentView *_scrollViewComponentView;
+  RCTScrollViewComponentView *__weak _scrollViewComponentView;
 }
 
 - (instancetype)initWithFrame:(CGRect)frame