feat: update tranistor approval for middle_purple_beaver until allowlist fixed

What

Template for the Upgrade tooling in tenant environments (PRODUCTION) issues (ie: https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/team/-/issues/9984) updated to include the recommendation that we prevent any Hosted Runner maintenance for middle_purple_beaver until they have whitelisted the new IPs for the green shard

Why

This is in order to prevent a reoccurence of the incident https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/incident-management/-/issues/543 We discussed this

• https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/team/-/issues/9984
• https://gitlab.slack.com/archives/C05Q5FFLSPP/p1758047980251929

This message should be removed once Luke Stahlman passes on the message from the customer that they have allowlisted the relevant ips. Only then should Hosted Runner maintenance be resumed on middle_purple_beaver