Per #3541, we only actually use v=1 shells and displays. Removing this support from the UI will allow us to remove a dependency on ws-shell and its sub-dependencies, which will at least lighten the bundle and give us fewer packages to keep updated.

I don't think there's any sense in keeping v2 -- nobody who still works here knows how it works, and anyway it would only be supported in docker-worker which is deprecated, so there's zero chance that we'll ever implement the worker side.