Fallback to time-based polling on a degoogled phone

[Requinard]

So it turns out the app actually works on a degoogled phone. Everything works EXCEPT for the FCM messages. As we cannot get this to work we should look into a fallback.

• Detect a degoogled phone
• Add time-based polling to the SyncManager. This will solve polling in the foreground
• Find a way to also execute this in the background.

[lukashaertel]

https://docs.expo.dev/versions/latest/sdk/background-fetch/

This might help out, we need to check if we can schedule notifications on this