[SaaS] Clarify note about churned customer and move under #domains-using-cf#25724

RebeccaTamachiro merged 1 commit intoproductioncloudflare/cloudflare-docs:productionfrom

rebecca/ssl4saas-update-remove-ch-docscloudflare/cloudflare-docs:rebecca/ssl4saas-update-remove-ch-docsCopy head branch name to clipboard