Valid devcontainer.metadata can corrupt compose override file

dev containers version: `v0.387.0`
OS: Ubuntu 24.04

## Description

I can't get a compose file to run through devcontainers even though it runs fine from command line. The culprit seems to be a corrupted 'Features Compose Override File' generation that I don't even know how to clear.

At one point my compose.yaml file had the following environment variable set:

```
ROSCONSOLE_FORMAT: "[$${severity}] [$${walltime:%Y-%m-%d %H:%M:%S}] [$${node}]: $${message}"
```

This works in the repro example below and has worked for me in the past with docker compose running from CLI. However, it complained while I was migrating to use compose + devcontainers. From the logs below, it seems like the dictionary was getting converted to a list, and the colon in the value field doesn't play nice:

```
[2024-09-24T19:43:41.966Z] Stop (354 ms): Run: docker build -f /tmp/devcontainercli-achille/updateUID.Dockerfile-0.71.0 -t vsc-dev-docker-afd93ed1eced211ffad11c8e3235c1ce630bab41c837eddba2a4841a56df1b38-uid --platform linux/amd64 --build-arg BASE_IMAGE=gmr/customer --build-arg REMOTE_USER=gmruser --build-arg NEW_UID=1000 --build-arg NEW_GID=1000 --build-arg IMAGE_USER=gmruser /home/achille/.config/Code/User/globalStorage/ms-vscode-remote.remote-containers/data/empty-folder
[2024-09-24T19:43:41.967Z] Docker Compose override file for creating container:
services:
'customer':
image: vsc-dev-docker-afd93ed1eced211ffad11c8e3235c1ce630bab41c837eddba2a4841a56df1b38-uid
entrypoint: ["/bin/sh", "-c", "echo Container started\n
trap \"exit 0\" 15\n
\n
exec \"$$@\"\n
while sleep 1 & wait $$!; do :; done", "-", "/entrypoint.sh"]
environment:
- USER=achille
- DISPLAY=:1
- NVIDIA_VISIBLE_DEVICES=all
- NVIDIA_DRIVER_CAPABILITIES=compute,utility,display
- XAUTHORITY=
- QT_X11_NO_MITSHM=1
- ROSCONSOLE_FORMAT='[${severity}] [${walltime:%Y-%m-%d %H:%M:%S}] [${node}]: ${message}'
labels:
- 'devcontainer.local_folder=/home/achille/gmr/dev-docker'
- 'devcontainer.config_file=/home/achille/gmr/dev-docker/.devcontainer/devcontainer.json'
- 'devcontainer.metadata=[{"postCreateCommand":"/bin/bash .devcontainer/postCreate_command.sh $${containerWorkspaceFolder}","customizations":{"vscode":{"settings":{"terminal.integrated.profiles.linux":{"bash":{"path":"bash"}},"terminal.integrated.defaultProfile.linux":"bash","remote.autoForwardPorts":false},"extensions":["dotjoshjohnson.xml","zachflower.uncrustify","ms-azuretools.vscode-docker","ms-iot.vscode-ros","ms-python.python","ms-vscode.cpptools-extension-pack","redhat.vscode-yaml","smilerobotics.urdf","streetsidesoftware.code-spell-checker","twxs.cmake","yzhang.markdown-all-in-one","github.vscode-github-actions","ms-vscode.cpptools","ms-vscode.cmake-tools"]}},"mounts":["type=bind,source=/var/log/.ros,target=/var/log/.ros","type=bind,source=$${localWorkspaceFolder}/persistent_data,target=/home/gmruser/.ss","type=bind,source=$${localWorkspaceFolder}/runtime_data,target=/home/gmruser/.ss_temp","type=bind,source=/etc/ss,target=/etc/ss","type=bind,src=$${localEnv:HOME}/.ssh,target=/home/gmruser/.ssh,readonly","type=bind,src=$${localEnv:HOME}/.ssh/known_hosts,target=/home/gmruser/.ssh/known_hosts","type=bind,src=$${localEnv:HOME}/.backport/config.json,target=/home/gmruser/.backport/config.json","type=volume,target=$${containerWorkspaceFolder}/build","type=volume,target=$${containerWorkspaceFolder}/install"],"containerEnv":{"USER":"$${localEnv:USER}","DISPLAY":"$${localEnv:DISPLAY}","NVIDIA_VISIBLE_DEVICES":"all","NVIDIA_DRIVER_CAPABILITIES":"compute,utility,display","XAUTHORITY":"$${localEnv:XAUTH}","QT_X11_NO_MITSHM":"1","ROSCONSOLE_FORMAT":"''[$${severity}] [$${walltime:%Y-%m-%d %H:%M:%S}] [$${node}]: $${message}''"},"remoteUser":"gmruser"},{"postCreateCommand":"/bin/bash .devcontainer/postCreate_command.sh $${containerWorkspaceFolder}","customizations":{"vscode":{"settings":{"terminal.integrated.profiles.linux":{"bash":{"path":"bash"}},"terminal.integrated.defaultProfile.linux":"bash","remote.autoForwardPorts":false},"extensions":["dotjoshjohnson.xml","zachflower.uncrustify","ms-azuretools.vscode-docker","ms-iot.vscode-ros","ms-python.python","ms-vscode.cpptools-extension-pack","redhat.vscode-yaml","smilerobotics.urdf","streetsidesoftware.code-spell-checker","twxs.cmake","yzhang.markdown-all-in-one","github.vscode-github-actions","ms-vscode.cpptools","ms-vscode.cmake-tools"]}},"mounts":["type=bind,source=/var/log/.ros,target=/var/log/.ros","type=bind,src=/etc/ss/,dst=/etc/ss","type=bind,src=$${localEnv:HOME}/.ssh,target=/home/gmruser/.ssh,readonly","type=bind,src=$${localEnv:HOME}/.ssh/known_hosts,target=/home/gmruser/.ssh/known_hosts","type=bind,src=$${localEnv:HOME}/.backport/config.json,target=/home/gmruser/.backport/config.json","type=volume,target=/workspaces/platform/build","type=volume,target=/workspaces/platform/install","type=volume,target=$${containerWorkspaceFolder}/build","type=volume,target=$${containerWorkspaceFolder}/install"],"containerEnv":{"USER":"$${localEnv:USER}","DISPLAY":"$${localEnv:DISPLAY}","NVIDIA_VISIBLE_DEVICES":"all","NVIDIA_DRIVER_CAPABILITIES":"compute,utility,display","XAUTHORITY":"$${localEnv:XAUTH}","QT_X11_NO_MITSHM":"1","ROSCONSOLE_FORMAT":"''[$${severity}] [$${walltime:%Y-%m-%d %H:%M:%S}] [$${node}]: $${message}''"},"remoteUser":"gmruser"},{"remoteUser":"gmruser"}]'
volumes:
[...]
- vscode:/vscode
volumes:

vscode:
external: true
```

This failed with the following error:
```
[2024-09-24T19:43:41.967Z] Writing docker-compose.devcontainer.containerFeatures-1727207021967-6e5554e4-df63-43ad-ab82-77c2b36e0506.yml to /home/achille/.config/Code/User/globalStorage/ms-vscode-remote.remote-containers/data/docker-compose
[2024-09-24T19:43:41.967Z] Start: Run: docker compose --project-name dev-docker -f /home/achille/gmr/dev-docker/compose.yaml -f /home/achille/.config/Code/User/globalStorage/ms-vscode-remote.remote-containers/data/docker-compose/docker-compose.devcontainer.containerFeatures-1727207021967-6e5554e4-df63-43ad-ab82-77c2b36e0506.yml up -d
[2024-09-24T19:43:42.015Z] WARN[0000] The "message" variable is not set. Defaulting to a blank string.
[2024-09-24T19:43:42.015Z] services.customer.environment.[6]: unexpected type map[string]interface {}
```

The first thing I did was to remove the offending `ROSCONSOLE_FORMAT` variable from my `compose.yaml` file. However, `Rebuild and reopen in container` will still yield the same error. I've tried reopening the window to no avail.

When I copy the command being run `docker compose --project-name dev-docker -f /home/achille/gmr/dev-docker/compose.yaml -f /home/achille/.config/Code/User/globalStorage/ms-vscode-remote.remote-containers/data/docker-compose/docker-compose.devcontainer.containerFeatures-1727207021967-6e5554e4-df63-43ad-ab82-77c2b36e0506.yml up -d` and modify the `containerFeatures` compose file and remove the offending line manually and then run this command from the terminal, it works fine. But this file gets regenerated every time I run 'reopen in container'.

I've tried:
* clearing the user data folder `rm -rf /home/achille/.config/Code/User/globalStorage/ms-vscode-remote.remote-containers/data`
* clearing all files in `~/.config/Code` dir that had a reference to `ROSCONSOLE_FORMAT`, including
* `~/.config/Code/User/globalStorage/state.vscdb`
* `~/.config/Code/User/workspaceStorage/594f8f796eef47d970635b16d002a443/state.vscdb`
* `rm /tmp/devcontainercli-achille/container-features/0.71.0-1727210272333/Dockerfile-with-features`
* `rm /var/lib/containerd/io.containerd.metadata.v1.bolt/meta.db`

EDIT: I've found that the issue stems from the devcontainer.metadata that's attached to the image being used. That image was created using devcontainers and has the `ROSCONSOLE_FORMAT` baked into it, which this compose override file generation seems to be using. Removing the environment variable from the original image solved the issue. I will update the repro repository accordingly.

## Repro

EDIT: repro [here](https://github.com/Achllle/devcontainer_issues)