Fix the crashes on first-run

[harinikmsft]

There are 2 crashes that consistently occur on first-run:

1. If chrome is not launched prior to the app launched, then there is C++ exception and the app crashes
2. On second try, the bundler/packager doesn't consistently package the RN JS file and hence the app does not refresh with the UI. Once I close the app and run it again, everything just works.

We need to fix both these issues so that developers can reliably launch the app on first-run by running the react-native run windows command.