iOS autolinking.rb needs to export react_native_pods.rb (#44462)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/44462

Users using the new `react-native/scripts/cocoapods/autolinking.rb` script will expect all of the helper methods previously exposed throug `react_native_pods.rb`.

This was an oversight.

Changelog: [iOS][Fixed] exposes react_native_pods methods through autolinking.rb

Reviewed By: cipolleschi

Differential Revision: D57066094

fbshipit-source-id: d65dc79430101c9c43cbd90d1456630e338a22bb