Add info for TAMs to proactively discuss upgrades

Support sometimes deal with preventable emergencies where large customers have started an upgrade without reading our documentation and without planning how to roll back. TAMs can play a part by reminding customers about the upgrade process at every touch point with the customer and share the Live Upgrade Assistance info. This commit adds that as a part of 'Relationship Management'

Example Zendesk ticket (internal only) from a customer: https://gitlab.zendesk.com/agent/tickets/135856 Resulted in a multiple hour call. cc @cbazan @k33g @christiaanconover - hoping y'all can share this info with your peers and add it to your email / meeting templates so it's always discussed with customers.