Sync when phone is in flightmode with VPN active

[sunkup]

Discussed in #755

^{Originally posted by Somebodyisnobody December 8, 2025}
First of all, it's hard to find the right category here: I shall not open a new issue for bugs and use discussions instead but there is no discussion category for bugs:

But let's move on:

1. Set up VPN (in my case Wireguard with "always active" enabled)
2. Set up ICSx5 to synchronize every 15 minutes
3. Enable VPN
4. Feel free to synchronize manually
5. Turn on flight mode
6. While (15 minutes since step 5 is not over): Get a coffee, drink the coffee, repeat
7. See a error notification in the notifications menu.

ICSx5 thinks there is a internet connection even if the flight mode is turned on. This is because Wireguard VPN keeps an active interface. VPN interfaces should not be taken into account. Only Ethernet, Wifi, Bluetooth or cellular should be taken into account.