MON-2853: add runbook link to TargetDown alert

[machine424]

• I added CHANGELOG entry for this change.
• No user facing changes, so no entry in CHANGELOG was needed.

[openshift-ci-robot]

@machine424: This pull request references MON-2853 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the task to target either version "4.16." or "openshift-4.16.", but it targets "Alongside OpenShift 4.13" instead.

In response to this:

• I added CHANGELOG entry for this change.
• No user facing changes, so no entry in CHANGELOG was needed.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[jan--f]

Thanks!
/lgtm

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jan--f, machine424

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• OWNERS [jan--f,machine424]

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[marioferh]

/test e2e-aws-ovn-single-node

[openshift-bot]

[ART PR BUILD NOTIFIER]

This PR has been included in build cluster-monitoring-operator-container-v4.16.0-202401171849.p0.gc8836f7.assembly.stream for distgit cluster-monitoring-operator.
All builds following this will include this PR.