Fix missing keyword: :comment on VulnerabilityRevertToDetected GraphQL mutation

Summary

Setting Vulnerability status back to Needs triage fails with Internal server error: missing keyword: :comment

Steps to reproduce

1. https://gitlab.com/gitlab-examples/security/security-reports/-/security/vulnerabilities/2695906
2. Try changing status to Needs triage

What is the current bug behavior?

Operation fails

What is the expected correct behavior?

Vulnerability status is changed to Needs triage