Fixes modal for GraphQL pipeline security report

What does this MR do and why?

We recently changed the name of an event emitted by the GraphQL finding modal's from hide to hidden. The GraphQL pipeline security report (behind feature flag) was not updated to listen to the new event and this broke the modal's functionality.

This MR fixes the issue.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

How to set up and validate locally

1. Have the related FF enabled: echo "Feature.enable(:pipeline_security_dashboard_graphql)" | rails c
2. You'll need an EE License
3. You'll need to have runners enabled (See $2408961 for setting up a runner)
4. Import https://gitlab.com/gitlab-examples/security/security-reports
5. Run a pipeline on master
6. Go to the pipeline page
7. Click on several findings and verify that the modal opens every time

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.