I got the following response from Garmin support regarding removing the ability to import GPX files using the iOS share function...
This was not an intended feature of Garmin Connect Mobile on any platform. You should not expect that to come back. If Garmin decides to add the ability to import 3rd party courses in the future, we'll do it directly thru the app and not the OS.
Very disappointing ... If you used this feature, I suggest you open a ticket with Support and indicate your displeasure (politely).
david