[E2E] PROMOTE TO BLOCKING: webhook_events_spec.rb

What does this MR do?

Promotes the following e2e tests to the blocking bucket:

1. Manage WebHooks integration sends an issues and note event | Testcase | Spec metrics

2. Manage WebHooks integration sends a wiki page event | Testcase | Spec metrics

3. Manage WebHooks integration sends a tag event | Testcase | Spec metrics

4. Manage WebHooks integration sends a push event | Testcase | Spec metrics

5. Manage WebHooks integration sends a merge request event | Testcase | Spec metrics

This MR was created based on data from reliable e2e test report: #493073 (closed)

(This MR was automatically generated by gitlab_quality-test_tooling at 2024-09-23 02:07:57 UTC)