This is done. Toolforge supports using Cloud Native Buildpacks, which automatically generate a Docker image for the project. So in other words, we don't have to manually build/maintain a Docker image. When we initiate a build in Toolforge, a Docker image is automatically created for us using buildpacks - and so this issue isn't really relevant now.

I have tested the buildpack-generated image multiple times and verified it works - so I'm closing this out.