Add logging to GetAuthenticatedUserId for debugging

#deploy-idporten-frontend

Added log statements to provide more context about the authentication object and token attributes during execution. This will help in identifying potential issues and understanding how authentication data is being processed. Also updated the default return value for unsupported contexts to an empty string instead of null.

libs/reactive-security/src/main/java/no/nav/testnav/libs/reactivesecurity/action/GetAuthenticatedUserId.java

@@ -1,6 +1,7 @@
 package no.nav.testnav.libs.reactivesecurity.action;
 
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.context.ReactiveSecurityContextHolder;
 import org.springframework.security.core.context.SecurityContext;
@@ -11,6 +12,7 @@
 
 import java.util.concurrent.Callable;
 
+@Slf4j
 @Component
 @RequiredArgsConstructor
 public class GetAuthenticatedUserId implements Callable<Mono<String>> {
@@ -37,14 +39,16 @@ private Mono<String> getTokenAttribute(String attribute) {
 
     private String getTokenAttribute(Authentication context, String attribute) {
 
+        log.info("context.authentication {}", context);
         if (context instanceof JwtAuthenticationToken jwtAuthenticationToken) {
             return jwtAuthenticationToken.getTokenAttributes().get(attribute).toString();
 
         } else if (context instanceof OAuth2AuthenticationToken oauth2AuthenticationToken) {
+            log.info("oauth2AuthenticationToken {}", oauth2AuthenticationToken.getPrincipal());
             return oauth2AuthenticationToken.getPrincipal().getAttributes().get(attribute).toString();
 
         } else {
-            return null;
+            return "";
         }
     }
 }