Added null check for authentication object

Closes spring-projectsgh-11510

Author: Karthikeyan R

core/src/main/java/org/springframework/security/authorization/AuthenticatedAuthorizationManager.java

@@ -143,7 +143,7 @@ private static final class FullyAuthenticatedAuthorizationStrategy extends Authe
 
 		@Override
 		boolean isGranted(Authentication authentication) {
-			return this.trustResolver.isFullyAuthenticated(authentication);
+			return authentication != null && this.trustResolver.isFullyAuthenticated(authentication);
 		}
 
 	}