Description

We return empty BuildInfo if root/buildinfo/content_manifests/*.json doesn't contain contentSets.
But if root/buildinfo/content_manifests/ doesn't have file with contentSets - we return error (because we don't use default contentSets)

That is why we need to return nil if contentSets are not found.

See #7911 to get example.

Related issues

• Close bug(redhat): we don't need to return error if redhat image doesn't contain content_sets  #7911

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).