Core: Generate manager cache in smoke test, but don't use/clear any cache

[ghengeveld]

Issue: -
Discussion: #13737

What I did

When running with --smoke-test, currently no manager cache is used, created or cleared. However, sometimes it's beneficial to be able to prepare (generate) a cached manager without actually starting Storybook, for example when preparing a Docker image with embedded manager cache. This change makes --smoke-test cache the manager it built like normal, but won't use or clear any cache it finds as was intended in #13266.

How to test

• Is this testable with Jest or Chromatic screenshots? no
• Does this need a new example in the kitchen sink apps? no
• Does this need an update to the documentation? no

If your answer is yes to any of these, please make sure to include it in your PR.

[shilman]

LGTM 🙏

[shilman]

@ghengeveld Unit test are failing, can you fix?

[phated]

@shilman I believe unit tests are failing because an old, bad cache is used when a new cache is not found. I submitted a PR at #13752 but it hasn't been reviewed/merged.

[phated]

@ghengeveld That PR has landed, but I think you need to rebase master to get that action base to run 🎉