Respect prop Text.allowFontScaling when sizing text

Summary:
changelog:
[iOS][Fixed] Fix Text.allowFontScaling prop in the new architecture

Reviewed By: javache

Differential Revision: D40643536

fbshipit-source-id: 1fb77b226089ce5e9ffc642b1d9a3de266d202c3

ReactCommon/react/renderer/textlayoutmanager/platform/ios/RCTAttributedTextUtils.mm

@@ -71,7 +71,8 @@ inline static UIFont *RCTEffectiveFontFromTextAttributes(const TextAttributes &t
   fontProperties.weight = textAttributes.fontWeight.has_value()
       ? RCTUIFontWeightFromInteger((NSInteger)textAttributes.fontWeight.value())
       : NAN;
-  fontProperties.sizeMultiplier = textAttributes.fontSizeMultiplier;
+  fontProperties.sizeMultiplier =
+      textAttributes.allowFontScaling.value_or(true) ? textAttributes.fontSizeMultiplier : 1;
 
   return RCTFontWithFontProperties(fontProperties);
 }