Record success rate of screenshot capture
Record success rate of screenshot capture

Summary: Android and iOS each have a separate metric

Reviewed By: passy

Differential Revision: D13763758

fbshipit-source-id: f679360ec0ee008b434bfe12107ac6548d882a1f

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper