Fix for Facebook posting

We've implemented a fix for the Facebook issue identified in this eBay Partner Network post: https://partnerhelp.ebay.com/helpcenter/s/article/Mobile-Deep-Linking?language=en_US#facebook_app . It involves correcting attribution when a user opens an ePN rover link from with the Facebook app. Note that the fix only affects the iOS app; there is no fix at this time for the Android app.