[5xx] Update troubleshooting-cloudflare-5xx-errors.mdx (#19193)

Isn't this info redundant in this context?  

### Error 526

Author: nenizera

src/content/docs/support/troubleshooting/cloudflare-errors/troubleshooting-cloudflare-5xx-errors.mdx

@@ -336,8 +336,6 @@ level](https://docs.nginx.com/nginx/admin-guide/monitoring/logging/).
 
 ## Error 526: invalid SSL certificate
 
-### Error 526
-
 Error 526 occurs when these two conditions are true:
 
 1. Cloudflare cannot validate the SSL certificate at your origin web server, and