[E2E] PROMOTE TO BLOCKING: email_notification_for_alert_spec.rb

What does this MR do?

Promotes the following e2e tests to the blocking bucket:

1. Monitor Alert when user is an owner when using Prometheus integration behaves like notification on new alert sends email to user | Testcase | Spec metrics

2. Monitor Alert when user is an owner when using HTTP endpoint integration behaves like notification on new alert sends email to user | Testcase | Spec metrics

3. Monitor Alert when user is a maintainer when using Prometheus integration behaves like notification on new alert sends email to user | Testcase | Spec metrics

4. Monitor Alert when user is a maintainer when using HTTP endpoint integration behaves like notification on new alert sends email to user | Testcase | Spec metrics

This MR was created based on data from reliable e2e test report: #472396 (closed)

(This MR was automatically generated by gitlab_quality-test_tooling at 2024-07-15 02:07:41 UTC)