wsl: Failed to start the systemd user session for '...'. See journalctl for more details.

### Windows Version

Microsoft Windows [Version 10.0.26200.7093]

### 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

Ubuntu 22.04

### Other Software

_No response_

### Repro Steps

From Windows PowerShell run `wsl.exe`.

Alternatively, start WSL from Windows Terminal.

### Expected Behavior

No messages about `systemd`, and Linux shell prompt appears for normal operation.

### Actual Behavior

After some delay (presumably for Linux to start) the following message appears.
```
wsl: Failed to start the systemd user session for 'marcusps'. See journalctl for more details.
```
after which the Linux shell promp appears and seems to behave normally (although occasional WSL crashes happen, unclear if connected).

### Diagnostic Logs

Will be e-mail to [wsl-gh-logs@microsoft.com](mailto:wsl-gh-logs@microsoft.com) separately.

Start by reproducing the report with `wsl.exe` or Windows Terminal on WSL 2 with Ubuntu 22.04, then inspect `journalctl` and the diagnostic logs for the systemd user-session failure. Done means WSL starts without the systemd warning and presents a normally functioning Linux shell.

Written by the indexing model from the issue text.