Dismissed vulnerabilities in Pipeline security tab are still showing up

Summary

In the Security tab of pipelines, dismissed vulnerabilities are hidden by default. Yet, some dismissed vulnerabilities are showing up.

Steps to reproduce

1. Go to https://gitlab.com/gitlab-com/gl-security/engineering-and-research/gib/-/pipelines/582858902/security
2. Check out the first finding --> Status = Dismissed
3. Toggle the Hide dismissed button
4. First finding still there

Example Project

https://gitlab.com/gitlab-com/gl-security/engineering-and-research/gib/-/pipelines/582858902/security

What is the current bug behavior?

1. Dismissed vulnerabilities should not appear in the list by default.
2. Dismissed vulnerabilities should not propose a Dismiss action in the modal

What is the expected correct behavior?

1. Hide dismissed vulnerabilities
2. Undo dismiss button instead of Dismiss

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes

/cc @thiagocsf @matt_wilson