fix: Fouten in implementatie van hello-mechanisme opgelost.

frontend/src/services/auth/auth-service.ts

@@ -92,6 +92,7 @@ async function handleLoginCallback(): Promise<void> {
         throw new Error("Login callback received, but the user is not logging in!");
     }
     authState.user = (await (await getUserManagers())[activeRole].signinCallback()) || null;
+    await apiClient.post("/auth/hello");
 }
 
 /**