Webhook Vulnerability event fails at top level group
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### Summary
Vulnerability Events is supported for both [Project and Group level Webhooks](https://docs.gitlab.com/user/project/integrations/webhook_events/#events-triggered-for-both-project-and-group-webhooks). The problem is if you use the `Test` button to trigger those events at the Group level, it would fail with this error and gives the impression that it is not working.
```
Hook execution failed. Ensure the project has vulnerabilities
```
However if you actually have valid [vulnerability events](https://docs.gitlab.com/user/project/integrations/webhook_events/#vulnerability-events), the webhook will work properly.
> A vulnerability event is triggered when:
> - A vulnerability is created.
> - A vulnerability’s status is changed.
> - An issue is linked to a vulnerability.
### Steps to reproduce
1. Create a [vulnerable project](https://gitlab.com/gitlab-org/security-products/demos/analyzer-configurations/semgrep/sast-getting-started) under a top level group.
2. Create a webhook at the top level group.
3. Click on the test button and see this error.
```
Hook execution failed. Ensure the project has vulnerabilities
```
4. On the top level group, go to `Secure > Vulnerability Report` and change the status of any vulnerability.
5. Go back to the group webhook and click `Edit`, observe that the request is successful.
### Example Project
<!-- If possible, please create an example project here on GitLab.com that exhibits the problematic
behavior, and link to it here in the bug report. If you are using an older version of GitLab, this
will also determine whether the bug is fixed in a more recent version. -->
https://gitlab.com/groups/kballon_ultimate_group/-/hooks/59519549/hook_logs/13779405614
### What is the current *bug* behavior?
The test button fails to re-create a vulnerability event.
### What is the expected *correct* behavior?
The test button should successfully create a vulnerability event.
### Relevant logs and/or screenshots
<!-- Paste any relevant logs - please use code blocks (```) to format console output, logs, and code
as it's tough to read otherwise. -->
- Test button error

- Successful webhook event


### Output of checks
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This bug happens on GitLab.com
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<!-- or follow up with an issue comment of `@gitlab-bot label ~"reproduced on GitLab.com"` if you do not -->
#### Results of GitLab environment info
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<details>
<summary>Expand for output related to GitLab environment info</summary>
<pre>
(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`)
</pre>
</details>
#### Results of GitLab application Check
<!-- Input any relevant GitLab application check information if needed. -->
<details>
<summary>Expand for output related to the GitLab application check</summary>
<pre>
(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)
</pre>
</details>
### Possible fixes
<!-- If you can, link to the line of code that might be responsible for the problem. -->
### Patch release information for backports
If the bug fix needs to be backported in a [patch release](https://handbook.gitlab.com/handbook/engineering/releases/patch-releases) to a version
under [the maintenance policy](https://docs.gitlab.com/policy/maintenance/), please follow the steps on the
[patch release runbook for GitLab engineers](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/patch/engineers.md).
Refer to the [internal "Release Information" dashboard](https://dashboards.gitlab.net/d/delivery-release_info/delivery3a-release-information?orgId=1)
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](https://handbook.gitlab.com/handbook/engineering/releases/internal-releases/) for single-tenant SaaS instances,
refer to the [internal release process for engineers](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/internal-releases/engineers.md?ref_type=heads).
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issue
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