State field is absent in container ls on some versions of Docker

[bwateratmsft]

Discovered in microsoft/vscode-docker#3724. Likely the user has an older version of Docker, I see from the screenshot that the docker context ls command also lacks the --format argument, which is not something we can work around. Still, if we can gracefully handle the missing State field that would be ideal.

[bwateratmsft]

I think we would need to find a canary field that suggests that State is absent. I'm not a big fan of that approach; it sounds very fragile / too heuristic.