Prune AFNetworking Preqs

This release limits explicit AFNetworking linking to AFNetworking/NSURLSession (which implicitly pulls in .../Security and .../Reachability).

This resolves a reported issue (ACE-289) of an App Store deprecated UI warning for use of UIWebView:

"ITMS-90809: Deprecated API Usage - Apple will stop accepting submissions of apps that use UIWebView APIs . See https://developer.apple.com/documentation/uikit/uiwebview for more information."