chore(authn/authz): Add logging for Fiat session filter to give error…

… visibility. (#974)

* chore(authn/authz): Add debug logging for Fiat session filter to give error visibility.

* chore: fix nit

* Fix duplicate wording

* Removed incorrect statement.

* Updated from debug->warn as there isnt any valid reason for an Authenticated request to not have a user in it

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

gate-core/src/main/groovy/com/netflix/spinnaker/gate/filters/FiatSessionFilter.groovy

@@ -76,6 +76,8 @@ class FiatSessionFilter implements Filter {
             SecurityContextHolder.clearContext()
           }
         }
+      } else {
+        log.warn("Authenticated user was not present in authenticated request. Check authentication settings.")
       }
     } else {
       if (log.isDebugEnabled()) {
@@ -103,3 +105,4 @@ class FiatSessionFilter implements Filter {
   void destroy() {
   }
 }
+