RN: Change `@{ => no}format` in React Files

Summary:
Instead of using `.prettierrc` to ignore the files sync'd from React, replace `format` with `noformat`.

This is necessary because currently, the version of Prettier used in React Native (v2.4.1) differs from the version used in React (v1.19.1). We can revert this when React is upgraded.

Changelog:
[Internal]

Reviewed By: ShikaSD

Differential Revision: D32129937

fbshipit-source-id: ca3b379edd732670a9a0b1b20b3f31bdad4b74aa