Frontend: Use GraphQL mutations to dismiss a finding

Summary

As the Vulnerability Feedback will be deprecated, we no longer will have access to the feedback id after dismissing a finding. This will prevent us from undo a dismiss. To overcome this problem, use the GraphQL mutations instead.

Implementation plan

• Use securityFindingDismiss mutation to dismiss the finding in mr_widget_security_reports file

Verification steps

• Go to gitlab-org/govern/threat-insights-demos/mr-widget-v2-verification!1 (closed)
• Click on a finding
• Dismiss it
• The modal should be closed and you should see a dismissed label

Reopening the modal should display the dismissed information. Try playing around by adding a dismissal comment, removing it, editing etc...

Bonus check: refresh the page during these steps to verify whether we really fixed the caching issue (when you dismiss a finding, refreshing the page should still display it as dismissed).