Add CF_RETURNS_NOT_RETAINED annotate for Objective-C method which returns Core Foundation object (#23122)

Summary:
Changelog:
----------

[iOS][Fixed] - Add CF_RETURNS_NOT_RETAINED annotate for Objective-C method which returns Core Foundation object
Pull Request resolved: #23122

Differential Revision: D13781898

Pulled By: cpojer

fbshipit-source-id: 5953fa24a3d06766affdcabdec96bd43c062bf1b

Author: zhongwuzw

Libraries/ART/RCTConvert+ART.h

@@ -15,15 +15,15 @@
 
 @interface RCTConvert (ART)
 
-+ (CGPathRef)CGPath:(id)json;
++ (CGPathRef)CGPath:(id)json CF_RETURNS_NOT_RETAINED;
 + (CTTextAlignment)CTTextAlignment:(id)json;
 + (ARTTextFrame)ARTTextFrame:(id)json;
 + (ARTCGFloatArray)ARTCGFloatArray:(id)json;
 + (ARTBrush *)ARTBrush:(id)json;
 
 + (CGPoint)CGPoint:(id)json offset:(NSUInteger)offset;
 + (CGRect)CGRect:(id)json offset:(NSUInteger)offset;
-+ (CGColorRef)CGColor:(id)json offset:(NSUInteger)offset;
-+ (CGGradientRef)CGGradient:(id)json offset:(NSUInteger)offset;
++ (CGColorRef)CGColor:(id)json offset:(NSUInteger)offset CF_RETURNS_NOT_RETAINED;
++ (CGGradientRef)CGGradient:(id)json offset:(NSUInteger)offset CF_RETURNS_NOT_RETAINED;
 
 @end