Improve the release app archive tests #4483
Description
See #4469 (comment) where we have a broken app archive. We have a temporary fix for this but to improve the release tests and ensure this doesn't happen in the future we need to:
- Move the unzipping archive steps inside the python script rather than in the CI script as this is much cleaner, fail loudly if this does not work
- Check if we actually found an app archive and fail loudly if we don't or if the release archive tests are not run for any reason