fix some reference to LearCredentialMachine

Author: javieralvarezin2

src/main/java/es/in2/vcverifier/security/filters/CustomAuthenticationProvider.java

@@ -116,7 +116,7 @@ private String getCredentialSubjectFromVerifiableCredential(Object verifiableCre
             return learCredentialEmployee.credentialSubjectLCEmployee().mandateLCEmployee().mandateeLCEmployee().id();
         } else if (verifiableCredential instanceof LEARCredentialMachine learCredentialMachine) {
             // Extrae y retorna el credentialSubject específico para `LEARCredentialMachine`
-            return learCredentialMachine.credentialSubjectLCMachine().mandateLCMachine().mandateeLCMachine().id();
+            return learCredentialMachine.credentialSubject().mandate().mandatee().id();
         }
 
         throw new OAuth2AuthenticationException(OAuth2ErrorCodes.INVALID_REQUEST);

src/main/java/es/in2/vcverifier/service/impl/VpServiceImpl.java

@@ -145,7 +145,7 @@ private String extractMandateeId(List<String> credentialTypes, Payload payload)
             return learCredentialEmployee.credentialSubjectLCEmployee().mandateLCEmployee().mandateeLCEmployee().id();
         } else if (credentialTypes.contains(LEARCredentialType.LEARCredentialMachine.getValue())) {
             LEARCredentialMachine learCredentialMachine = mapCredentialToLEARCredentialMachine(vcObject);
-            return learCredentialMachine.credentialSubjectLCMachine().mandateLCMachine().mandateeLCMachine().id();
+            return learCredentialMachine.credentialSubject().mandate().mandatee().id();
         } else {
             throw new InvalidCredentialTypeException("Invalid Credential Type. LEARCredentialEmployee or LEARCredentialMachine required.");
         }