Systemd user session fails to start on OracleLinux_8_10 if it is not the first distro started

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### Windows Version

Microsoft Windows [Version 10.0.26200.7171]

### WSL Version

2.6.2.0

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

- [x] WSL 2
- [ ] WSL 1

### Kernel Version

6.6.87.2-1

### Distro Version

Oracle Linux 8.10

### Other Software

_No response_

### Repro Steps

1. Install wsl on Windows 11 (wsl --install)
2. Install Ubuntu (if not already installed) and run first user setup
3. Install OracleLinux_8_10 (OEL 8.10) from MS Store and run first user setup
4. Enable systemd on OEL 8.10 (/etc/wsl.conf [boot]\nsystemd=true)
5. Shut down wsl (wsl --shutdown)
6. Launch Ubuntu (wsl -d Ubuntu)
7. systemd user session is ok (systemctl status --user)
8. Launch OEL 8.10 (wsl -d OracleLinux_8_10)
9. see error "wsl: Failed to start the systemd user session for 'user'. See journalctl for more details."
10. systemd user session is not good (systemctl status --user) gets error "Failed to connect to bus: No such file or directory")

Reversing the WSL instance start order (OEL 8.10 first then Ubuntu) will result in both instances having working systemd user sessions.

Note this worked fine on WSL 2.4.13.0

### Expected Behavior

systemd user session operates successfully regardless of distribution launch order.

### Actual Behavior

systemd user session fails to start in OEL 8.10 unless it is the first distribution to be started

### Diagnostic Logs

[WslLogs-2025-12-07_17-33-01.zip](https://github.com/user-attachments/files/24014071/WslLogs-2025-12-07_17-33-01.zip)

Start by reproducing the launch-order difference with `wsl --shutdown`, `wsl -d Ubuntu`, and `wsl -d OracleLinux_8_10`, then inspect the attached WSL logs and `journalctl` output. Done means the Oracle Linux systemd user session works with `systemctl status --user` regardless of which distribution was started first.

Written by the indexing model from the issue text.