Windows sets virtual network adapter down

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### Windows Version

Microsoft Windows [Version 10.0.26100.7392]

### WSL Version

2.6.2.0

### Are you using WSL 1 or WSL 2?

- [x] WSL 2
- [ ] WSL 1

### Kernel Version

6.6.87.2-microsoft-standard-WSL2

### Distro Version

Arch Linux

### Other Software

Vagrant: 2.4.9
With provider:
Oracle VirtualBox: 7.2.4

### Repro Steps

Using mirrored networking
Starting a VM, using virtualbox "Host-Only Adapter" which assigns addresses on `192.168.56.1/24`

By default this adapter is mirrored _but_ not assigned an ip or enabled. Looking through `ipconfig.exe /all` the physical address can be found. Looking in `ip link` the interface can be determined.
Assume `eth3` is the interface, enable the interface like so:

sudo ip addr add dev eth3 192.168.56.1/24
sudo ip link set eth3 up

Then connectivity works between vms and wsl.

### Expected Behavior

1. That this adapter is enabled automatically. At least i expect this is what "mirrored" implies
2. That the adapter stays up

### Actual Behavior

The adapter goes down at random intervals(seconds or minutes). In linux, with the errors:
```
systemd-networkd[93]: eth3: Link DOWN
systemd-networkd[93]: eth3: Lost carrier
```

From what i see in logs this seems to be as a result of some dns change reapplying the network state before adapter is set up

### Diagnostic Logs

I managed to catch a pretty clean log file
[WslLogs-2025-12-22_08-39-43.zip](https://github.com/user-attachments/files/24287777/WslLogs-2025-12-22_08-39-43.zip)

Reproduce the issue with WSL 2 mirrored networking, an Oracle VirtualBox Host-Only Adapter, and the shown ip commands. Start by reviewing the attached WslLogs archive alongside the systemd-networkd Link DOWN and Lost carrier messages, especially around DNS changes. Done means the adapter is enabled as expected and remains up without recurring connectivity loss.

Written by the indexing model from the issue text.