Rollout `add_severity_system_note` feature flag

What

Remove the :add_severity_system_note feature flag ...

Owners

• Team: Monitor::Health
• Most appropriate slack channel to reach out to: #g_monitor_health
• Best individual to reach out to: Vitali Tatarintev (@ck3g)

Expectations

What are we expecting to happen?

What might happen if this goes wrong?

What can we monitor to detect problems with this?

Beta groups/projects

If applicable, any groups/projects that are happy to have this feature turned on early. Some organizations may wish to test big changes they are interested in with a small subset of users ahead of time for example.

• https://gitlab.com/gitlab-examples/ops/incident-setup/everyone/tanuki-inc project

Roll Out Steps

• Enable on staging
• Test on staging
• Ensure that documentation has been updated (docs MR !43566 (merged))
• Enable on GitLab.com for individual groups/projects listed above and verify behaviour
• Coordinate a time to enable the flag with #production and #g_delivery on slack.
• Announce on the issue an estimated time this will be enabled on GitLab.com
• Enable on GitLab.com by running chatops command in #production
• Cross post chatops slack command to #support_gitlab-com (more guidance when this is necessary in the dev docs) and in your team channel
• Announce on the issue that the flag has been enabled
• Remove feature flag and add changelog entry
• After the flag removal is deployed, clean up the feature flag by running chatops command in #production channel