Sort vulns by Location.Dependency.Version

What does this MR do?

Update Report.Sort() to sort Vulnerabilities by Severity, CompareKey, and Location.Dependency.Version (if available)

See this comment for background on why this is necessary.

What are the relevant issue numbers?

Update integration-test project to skip fields ... (gitlab-org/gitlab#336332 - closed)

Testing

Tested in this pipeline

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
• Ensure the report version matches the equivalent schema version
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer