Investigate networking of background app processes

[rfmejia]

It seems networking for background apps is disabled after some time. This is despite setting unrestricted battery usage and background data in app info settings.

For example, I stream music in NewPipe or AntennaPod and turn off the screen. Playback is fine on the stock ROM but on gargoyle it stops after a few minutes with a network error. To continue playback I have to unlock the device and start the stream. Note that playback of offline content is unaffected.

I am unsure if this is related to other issues such as Gadgetbridge notifications (as reported on Discord), or how strict doze mode works on Android 13/LineageOS 20.