feat(formanswer): log any failure when saving a answer

Author: btry

inc/formanswer.class.php

@@ -1209,6 +1209,10 @@ public function post_addItem() {
             'plugin_formcreator_questions_id'    => $questionId,
             'answer'                             => Toolbox::addslashes_deep($answer_value),
          ], [], 0);
+         if ($answer->isNewItem()) {
+            $formanswerId = $this->getID();
+            trigger_error("Formcreator: failed to save answer for question $questionId in formanswer ID $formanswerId. Value was: $answer_value", E_USER_WARNING);
+         }
          foreach ($field->getDocumentsForTarget() as $documentId) {
             $docItem = new Document_Item();
             $docItem->add([