don't create test artefacts in repo root

[LesnyRumcajs]

Summary of changes

Changes introduced in this pull request:

• more checks for actors bundle,
• don't create test artefacts in the repo root (without this change, each invocation of make test would create actor_bundles.car.zst in the root, making the directory dirty)

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.