wolfictl adv guide: allow user to continue with advisory modifications after execution

[luhring]

Today the command manages the clone and modification of advisory data in a temporary directory, in hopes of opening a PR with these changes on behalf of the user. But it doesn't easily let the user take control of the modification and PR process, should the command fail to work for any reason (e.g. lack of GitHub auth).

We should make sure to allow the user to escape the guide command and continue with their work if they want to, at minimum by sharing the temporary directory where their git clone exists.