Fix app name / package replacement

[zoontek]

Summary

Currently, app name / package replacement is kinda broken.

What are the steps to reproduce?

Let's say we have this scenario: My app name is Swan, my app package is io.swan.id. With this config, on the current version of the upgrade helper, you will notice that the app name is append to the app package, making it io.swan.id.swan

This is visible in paths or if you copy file raw content:

---

This PR fixes all of this. It also:

• Fixes the app package placeholder
• Fixes the tests (which are actually expecting an incorrect result, as we can also see that the app name is appended)
• Continues to use com.${appName.toLowercase()} if app name is set, but app package is not

Test Plan

Check both files content and paths with:

• no app name + no app package
• an app name but no app package
• an app name and an app package

Checklist

• [x] I tested this thoroughly
• [ ] I added the documentation in README.md (if needed)

[pvinis]

can you try on the netlify preview to see if it works as you expect?

[zoontek]

@pvinis Just checked it, works correctly ✅