Revert "Tools: Added eslint rule arrow-parens"

This reverts commit 0b6f5581f0.

It causes too many conflicts with pull requests.

ReactNativeClient/lib/components/note-body-viewer.js

@@ -240,7 +240,7 @@ class NoteBodyViewer extends Component {
 								allowFileAccess={true}
 								onLoadEnd={() => this.onLoadEnd()}
 								onError={() => reg.logger().error('WebView error')}
-								onMessage={(event) => {
+								onMessage={event => {
 									// Since RN 58 (or 59) messages are now escaped twice???
 									let msg = unescape(unescape(event.nativeEvent.data));