At the moment Firebase AB test goals always are "Total users who triggered this event". For many experiments it would be useful to have the "Total number of times this event was triggered" as the goal metric.

This could be made possible by adding a toggle to the goal event selection, where you can choose between unique or absolute event counts.

Example:
I am running a test that has the goal to increase the total screen views of "Screen A". At the moment, if I set a goal metric of "viewedscreena" (custom event), Firebase will tell me that the event wasn't successful when the number of users who triggered this event is lower in my variant than in control. This will happen even when the total number of events per user triggered in group a is higher.