maybe it's possible to be more clever here, so that we can fallback to /system here instead of relying on setting the external environment variable on reset-gaia.

For example, this works for me:
```bash
adb shell 'cat /data/local/webapps/webapps.json || echo \"basePath\": \"/system\"' | grep -s '"basePath": "/system'
```

You can probably simplify the regexp in the grep expression so that the echo is simpler too.