feat: add logging for empty secret

Security/Services/AuthService.cs

@@ -145,7 +145,13 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
             case TwoFactorAuthenticator.Totp:
                 {
                     if (string.IsNullOrEmpty(firstTokenAuth.Secret))
+                    {
+                        logger.LogWarning("The user {Fingerprint} for {UserId} tried to pass the 2FA even though the secret is empty",
+                            requestContext.Fingerprint,
+                            firstTokenAuth.UserId);
+
                         throw new InvalidOperationException("Required authentication data is missing.");
+                    }
 
                     var totp = new TotpService(firstTokenAuth.Secret);