When no network available: never try to sync

[gnu1dea]

🐞 Describe the bug

ntfy tries every 2 minutes to connect to the server even though there aren't any networks online (airplane mode + WLAN off)

💻 Components impacted

The Android app

🔮 Additional context

I started using RethinkDNS 0.5.5e: that's when I noticed all the apps that tried to connect when Android was offline

Maybe Jonas Kalderstam's approach can be somewhat useful here too: spacecowboy/Feeder@166390e

[Mikaela]

I think this is also tracked at celzero/rethink-app#1157 which contains a couple of other apps with workarounds for airplane mode + Rethink.