[Olauncher dev here] There's no Firebase integration in the Olauncher and never was. It literally collects no data. The releases on the Play Store, F-Droid and Github releases [APK] are all built from the same codebase, which is available on Github. Not sure why it's flagged.
If the developer is building the code that's on GitHub, it is curious why AppGoblin flags the Play Store version for using Firebase: https://appgoblin.info/apps/app.olauncher/data-flows