Fix: multiline textinput start "jerking" when trying to move cursor. (#32179)

Summary:
Fixes #30748: on iOS 14, when trying to hold down the space bar and move the cursor on a multi-line TextInput with lots of lines, the cursor could not be scrolled to the desired point. It works as expected on iOS 13 and before.

Figured out that iOS14 acting as expected without `[setContentOffset:animated:]`, so exclude it when iOS version is and above 14.

Credit to efstathiosntonas for the finding and solution provides.

## Related issue
- #30748

## Changelog

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[iOS] [Fixed] - Fixed the issue when moving cursor in multi-line TextInput.

Pull Request resolved: #32179

Test Plan:
1. Launch RNTester app on iOS
2. Open `TextInput` in tab `Components`
3. Scroll to `Multiline` section and focus on the first child
4. Input lots of dummy texts
5. Hold the space bar (on device) or press down the mouse inside `TextInput` (simulator without showing keyboard)

### **Video Before:**
https://user-images.githubusercontent.com/6382178/132800651-fb7cd2ac-fbd1-4ec4-9e3b-c06ab5b6a114.MP4

### **Video After:**
https://user-images.githubusercontent.com/6382178/132800677-f349fe7f-5902-40ff-8b93-ecc96ce29166.MP4

Reviewed By: philIip

Differential Revision: D31404248

Pulled By: lunaleaps

fbshipit-source-id: 74a39106e628602c5177fc243783288fcb7782fa

Author: xiankuncheng

Libraries/Text/TextInput/Multiline/RCTUITextView.m

@@ -182,12 +182,14 @@ - (void)paste:(id)sender
   _textWasPasted = YES;
 }
 
+// Turn off scroll animation to fix flaky scrolling.
+// This is only necessary for iOS <= 13.
+#if defined(__IPHONE_OS_VERSION_MAX_ALLOWED) && __IPHONE_OS_VERSION_MAX_ALLOWED < 140000
 - (void)setContentOffset:(CGPoint)contentOffset animated:(__unused BOOL)animated
 {
-  // Turning off scroll animation.
-  // This fixes the problem also known as "flaky scrolling".
   [super setContentOffset:contentOffset animated:NO];
 }
+#endif
 
 - (void)selectAll:(id)sender
 {