Refactor jobs container spec to Vue test utils

What does this MR do?

Let's use Vue test utils 🎉

Related to: #320934 (closed)

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because this is a developer only change.
• [ - ] Documentation (if required)
• Code review guidelines
• [ - ] Merge request performance guidelines
• [ - ] Style guides
• [ - ] Database guides
• [ - ] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [ - ] Tested in all supported browsers
• [ - ] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

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• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
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