Audit Event streaming event filtering no longer working v18.2.0

Summary

Since v18.2.0, it seems that Streaming Audit Events filtering by event type is no longer working.

Steps to reproduce

This was reproducible on v18.2.0, but not reproducible on v18.1.0.

1. Create a streaming audit event HTTP endpoint with event type filters only on changes to CI/CD variables.
2. Create a Git tag in the GitLab UI.

Example Project

What is the current bug behavior?

Streaming audit event HTTP endpoint receives event payload for event type not in filter.

What is the expected correct behavior?

Only filtered event types should be sent to the HTTP endpoint.

Relevant logs and/or screenshots

Output of checks

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

Patch release information for backports

If the bug fix needs to be backported in a patch release to a version under the maintenance policy, please follow the steps on the patch release runbook for GitLab engineers.

Refer to the internal "Release Information" dashboard for information about the next patch release, including the targeted versions, expected release date, and current status.

High-severity bug remediation

To remediate high-severity issues requiring an internal release for single-tenant SaaS instances, refer to the internal release process for engineers.