Pass on launcherEnabled flag

Summary:
This is a bit embarrassing. It seems like I never wired this up which is
why the update indicator keeps coming up even if the app was started
by the Launcher.

This actually makes sure that we proxy the yargs flag through to
`processConfig`.

Reviewed By: jknoxville

Differential Revision: D17341896

fbshipit-source-id: 73602e2035c26fb0d03e853a4e94065af3986757

static/setup.js

@@ -48,6 +48,7 @@ module.exports = function(argv) {
   config = {
     ...config,
     updaterEnabled: argv.updater,
+    launcherEnabled: argv.launcher,
     launcherMsg: argv.launcherMsg,
   };