Use already checked out git environment when git fetch fails

What does this MR do?

It's unlikely that users will have an environment that drops all ip tables like our QA offline test: https://gitlab.com/gitlab-org/security-products/tests/secrets/-/blob/offline-FREEZE/.gitlab-ci.yml#L39-41, but we should support some form of scanning if they truly are running in an offline environment. This will also unblock us on fixing the qa tests.

What are the relevant issue numbers?

N/A

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer