Until recently, it was possible in the app to create Campaigns that had "clicked an ad from this campaign" as a Goal. This was intended to be a one-click, easy set up option to explain and demonstrate the idea of a Campaign Goal.
Over time, we have learned from our customers that having this option available has done more harm than good. It makes reporting difficult to understand later on in the life of a Campaign or an Event, since it is often difficult to separate "real" Conversions from "click" conversions later on.
For this reason, we have decided to remove this option for Campaign Goals going forward. Your existing Campaigns that are using the ad click Goal option will not be affected, but you are encouraged to remove those goals and replace them as appropriate with more meaningful goals that represent Conversions for your marketing objectives.