`skip doctor`/`skip checkup` doesn't attempt to connect to the Android emulator

[dfabulich]

If you skip create or skip init an app project, by default, it's going to be configured to attempt to launch your app whenever you build.

skip checkup attempts to build and export an IPA and an APK, but it won't attempt to test installing/accessing a running emulator. It won't even run adb to see if it can detect a device.

We've recently had reports on Slack of users having issues during Skip build, not finding running emulators. Ideally, skip doctor would run adb devices to ensure that we can detect a running device, and skip checkup would install the app on a running device, allowing us to reproduce any issues with a single command.

[marcprux]

That's a good idea. Maybe it could be a flag like skip checkup --run, or skip checkup --run ios-simulator --run android-emulator to be able to pick multiple run targets.