[desktop-lite] XFCE4 Terminal fails on Debian 12 Bookworm

On Debian 12 Bookworm, the XFCE4 terminal fails to load inside of NoVNC (using the `desktop-lite` feature):

```
Failed to fdwalk: Operation not permitted
```

I’m not 100% sure about the cause (discussed further in mviereck/x11docker#346), but there’s some interaction occurring on systems which use `vte3>=0.63.91`. The workaround for now is to add the following to your `runArgs` in `devcontainer.json`:

```json
{
"runArgs": ["--security-opt", "seccomp=unconfined"]
}
```

I’m not 100% sure what the best call for this repo should be (maybe moving away from `xfce4-terminal`?), but I figured I’d report the issue and include a workaround in case anyone else runs into this :)