it needs to ship pass then…
snap packages have to be self contained so they can run everywhere, no matter if they are classic or strict …
if running pass is a hard requirement for your app to run, the snap needs to ship it (if the app has the path hard-coded you can use a layout to re-map it to the correct place, if your app just requires $PATH, then pass as shipped in the snap should just be found (the snap content is by default added to $PATH))