Fix issue where TypeScript errors in scripts/ folder weren't picked up

Summary: This diff fixes an issue where the `scripts` folder wasn't automatically type checked by TypeScript, and as a result `yarn flipper-server` was broken atm.

Reviewed By: nikoant

Differential Revision: D33348825

fbshipit-source-id: 059a834cacb881d45ae4b0933af3f1feabb90182

desktop/scripts/start-dev-server.ts

@@ -22,6 +22,7 @@ import fs from 'fs-extra';
 import {hostname} from 'os';
 import {compileMain, prepareDefaultPlugins} from './build-utils';
 import Watchman from './watchman';
+// @ts-ignore no typings for metro
 import Metro from 'metro';
 import {staticDir, babelTransformationsDir, rootDir} from './paths';
 import isFB from './isFB';