Detect Sites With /ping endpoint issues and take action

Some Scenarios,

- User removed the DNS record of custom domain, so site becom unreachable
- User put some cloudflare captcha or some layer in front, so that /api/method/ping endpoint never return correct data

We should auto detect and take some action so that those don't appear as noise in our uptime metrics
- Remove redirects and keep *.frappe.cloud for monitoring
- Stop monitoring for the site and alert them about the issue.