Deployment: The GTN can't be deployed from Gitpod (ONA) due to an error in the .devcontainer/devcontainer.json. fail in building the devcontainer

```
Your dev container failed to start due to:
Failed to pull or build dev container image: failed to build dev container image: failed to build dev container image: failed to build devcontainer: No image information specified in devcontainer.json.

Please:
- Review the logs: gitpod environment devcontainer logs
- Update your dev container configuration as needed: .devcontainer/devcontainer.json
- Rebuild: gitpod environment devcontainer rebuild

This container is temporary and will be removed after a successful rebuild.
For more information, refer to the documentation: https://ona.com/docs/flex/configuration/devcontainer
[recovery] root@ip-100-64-153-76:/workspaces/training-material#

```

Start with .devcontainer/devcontainer.json and review the Gitpod environment devcontainer logs for the reported missing image information. Rebuild with the documented devcontainer rebuild command; the work is done when the GTN devcontainer starts successfully from Gitpod (ONA).

Written by the indexing model from the issue text.