No way to delete a stack locally whose branches are deleted

[rd-borislav-rangelov]

Context

Our repo has the "Delete head on merge" option, which makes it so that when merging a stack from the GitHub website, the feature branches get deleted also.
Locally, I also ran gh stack sync which prompted me to prune the branches.

The stack remained for some reason (I see there's a related bug), so I tried to unstack it locally since it no longer existed on remote.

Issue / Feature request

I expected that gh stack unstack --local would destroy the stack even if the branches do not exist but it failed.

To clean my local repo, I had to re-create the branches in the stack with the same names and then unstack succeeded.

Is it possible to have unstack in the case where both the local & remote branches no longer exist to consider them pruned, skip them, and not fail?