[BUGFIX] Show correct message on server side validation error

Merge branch 'typo3-13' of github.com:in2code-de/femanager into typo3-13

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,
                     );