fix: Removal of BackHandler.removeEventListener in react-native#339

vonovak merged 2 commits intoexpo:masterexpo/react-native-action-sheet:masterfrom

dprevost-LMI:issues-337-fix-BackHandler.removeEventListenerdprevost-LMI/react-native-action-sheet:issues-337-fix-BackHandler.removeEventListenerCopy head branch name to clipboard