VPN does not handle switching networks very well.

### Describe the Bug

I've been using Pangolin for a while now, and really enjoy it, and decided to deploy it on a few edge clients. i.e. Android phones, tablets, etc.

I've noticed that when I leave the office (disconnect from WiFi) my VPN drops, and glitches out to the point where the app is unresponsive and I can't kill the VPN without doing it from system settings.

I cannot enable always-on VPN in settings as mentioned in #12 which may be part of the problem.

When I "hop" networks things tend to go awry, and to reset, I have to kill the VPN from settings and flick it back on.

### Environment

- OS Type & Version: Android 10.0.0 - Sonim XP8
- Pangolin Version: 1.15.1
- Gerbil Version: 1.3.0
- Traefik Version: 3.6.7
- Newt Version: 1.9.0
- Client Version: 0.1.7

Use case: Punching SIP traffic over VPN. (Works great! Except for these small hiccups!)

### To Reproduce

Connect to VPN via app, switch networks. (WiFi -> LTE, WiFi -> WiFi, LTE -> WiFi)

### Expected Behavior

Connection should not drop / app should not hang.