Remove '===', invalid syntax

Author: Maleware

docs/modules/nifi/pages/usage_guide/monitoring.adoc

@@ -48,9 +48,7 @@ IMPORTANT: If NiFi is configured to do any user authentication, requests to the
 === Authentication with NiFi `2.x.x`
 
 [IMPORTANT]
-===
 The NiFi metrics endpoints are behind a strong authentication mechanism which require credentials for each individual pod.
-===
 
 To authenticate, you can use a bearer token created by your NiFi instance e.g.