Show warning when exporting empty data
Show warning when exporting empty data

Summary: Shows warning when requiredplugin has empty data. It also makes the validation box as an error one, to distinguish between the two boxes.

Reviewed By: passy

Differential Revision: D19704910

fbshipit-source-id: ffd9413c3cd65c09f8b6019889191decefa6b6f6

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