Summary:
Update reference to property in code comment in `RCTImageLoader`. There is no protocol named `RCTImageCacheDelegate` in the codebase. Its just `RCTImageCache` and it exists [here](f2894e58cf/Libraries/Image/RCTImageLoader.h (L22)).
Pull Request resolved: https://github.com/facebook/react-native/pull/22406
Differential Revision: D13373793
Pulled By: cpojer
fbshipit-source-id: b5edf18ebad626bf09648c079299e5acd14ba48a