Error Message: 'Flutter/Flutter.h' file not found

Steps to reproduce:

1. Create an add 2 app scenario
2. Edit the module's pubspec.yaml to include a new asset
3. Inside of the module run flutter build bundle
4. Go back to your xcode project and build and run, notice that the Flutter headers are no longer able to be found.

You can fix this broken state by going back to your host app and running pod install.

It would be nice if we could automatically fix this erroneous state or communicate back to users that they need to run pod install again.