[BUGFIX] Show correct message on server side validation error

Merge pull request #701 from sgrossberndt/bugfix/error-message-server-side-validation

Author: sbusemann

Classes/Domain/Service/ValidationService.php

@@ -34,7 +34,7 @@ public function doServersideValidation(User $user, ServerRequestInterface $reque
                 foreach ($errors as $error) {
                     $validationErrors[] = GeneralUtility::makeInstance(
                         FlashMessage::class,
-                        LocalizationUtility::translate('validationErrorUniqueDb', 'femanager', $error->getArguments()),
+                        LocalizationUtility::translate($error['message'], 'femanager', $error->getArguments()),
                         $error->getTitle(),
                         ContextualFeedbackSeverity::ERROR,
                     );