desktop-lite feature: The desktop-lite feature is not enabling VNC password authentication

I've found that VNC password authentication is not being enforced in the desktop-lite feature. Here's a reproducible scenario:

Directory Structure

```
dvc-desktop-lite/
├── .devcontainer
│ └── devcontainer.json
└── compose.yaml
```

devcontainer.json

```json
{
"name": "dvc-desktop-lite",
"dockerComposeFile": "../compose.yaml",
"features": {
"ghcr.io/devcontainers/features/desktop-lite:1.2.5": {
"version": "latest",
"password": "vscode11"
}
},
"service": "dvc-desktop-lite",
"runServices": [
"dvc-desktop-lite"
],
"remoteUser": "node",
"shutdownAction": "stopCompose",
"workspaceFolder": "/home/node",
"forwardPorts": [
6080,
5901
],
"portsAttributes": {
"6080": {
"label": "novnc"
},
"5901": {
"label": "tigervnc"
}
}
}
```

compose.yaml

```yaml
name: dvc-desktop-lite
services:
dvc-desktop-lite:
image: mcr.microsoft.com/devcontainers/typescript-node:22-bookworm
init: true
tty: true
user: node
working_dir: /home/node
```

With the above files prepared, start the development container by `Dev Containers: open Folder in Container`

Then, open in a web browser. The VNC screen will be displayed without authentication.

To enable VNC password authentication, modify the compose.yaml file as follows:

```yaml
name: dvc-desktop-lite
services:
dvc-desktop-lite:
image: mcr.microsoft.com/devcontainers/typescript-node:22-bookworm
init: true
tty: true
user: node
working_dir: /home/node
environment:
VNC_PASSWORD: enable
```

This is caused by the following process in /usr/local/share/desktop-init.sh, which is generated by install.sh.

```bash
if [ -n "${VNC_PASSWORD+x}" ]; then
startInBackgroundIfNotRunning "Xtigervnc" sudoUserIf "${common_options} -passwd /usr/local/etc/vscode-dev-containers/vnc-passwd"
# (snip)
fi
```

By modifying the configuration as shown below, I was able to achieve the desired behavior and enable VNC password authentication. The password used for authentication in this case was "vscode11", which was specified in the devcontainer.json file.

```bash
if [ -e "/usr/local/etc/vscode-dev-containers/vnc-passwd" ]; then
startInBackgroundIfNotRunning "Xtigervnc" sudoUserIf "${common_options} -passwd /usr/local/etc/vscode-dev-containers/vnc-passwd"
# (snip)
fi
```

Previously, VNC password authentication was enabled without specifying any environment variables, but now it requires the VNC_PASSWORD environment variable to be set.

If this is the intended behavior, I would appreciate it if you could document this change.