Summary:
Set duration=0 for android keyboard events. Brings actual implementation closer to existing flowtypes, and duration is set to 0 to minimize impact on existing keyboard event consumers.
Follow up to #24947, upon cpojer's [input](https://github.com/facebook/react-native/pull/24947#issuecomment-494681618) :)
## Changelog
[Android] [Added] - Set duration=0 for android keyboard events
Pull Request resolved: https://github.com/facebook/react-native/pull/24994
Differential Revision: D15449394
Pulled By: cpojer
fbshipit-source-id: d43096238bd38d189fbec54fc2d93f17010d9ddb