UNOTOPLYS-319 : Correction de la sérialisation

src/main/java/com/unantes/orientactive/converter/bean/MultipleChoiceItem.java

 package com.unantes.orientactive.converter.bean;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.unantes.orientactive.export.ExportableItem;
 import com.unantes.orientactive.web.api.model.ChoiceAPI;
 import com.unantes.orientactive.web.api.model.MultipleChoiceItemAPI;
@@ -65,6 +66,7 @@ public class MultipleChoiceItem extends AbstractQuestion implements ExportableIt
         }
     }
 
+    @JsonIgnore
     @Override
     public List<String> getExportAnswersLabels(List<String> answers) {
         return answers.stream().map(this::getLabelForValue).collect(Collectors.toList());
@@ -74,6 +76,7 @@ public class MultipleChoiceItem extends AbstractQuestion implements ExportableIt
         return choices.stream().filter(choice -> choice.getValue().equals(code)).findFirst().orElseThrow().getLabel();
     }
 
+    @JsonIgnore
     @Override
     public String getExportQuestionLabel() {
         if (StringUtils.isBlank(shortLabel)) {
@@ -82,6 +85,7 @@ public class MultipleChoiceItem extends AbstractQuestion implements ExportableIt
         return shortLabel;
     }
 
+    @JsonIgnore
     @Override
     public String getExportQuestionReference() {
         return reference;

src/main/java/com/unantes/orientactive/converter/bean/OpenQuestion.java

 package com.unantes.orientactive.converter.bean;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.unantes.orientactive.export.ExportableItem;
 import com.unantes.orientactive.web.api.model.OpenQuestionItemAPI;
 import org.apache.commons.lang3.StringUtils;
@@ -33,6 +34,7 @@ public class OpenQuestion extends Item implements ExportableItem {
         super();
     }
 
+    @JsonIgnore
     @Override
     public OpenQuestionItemAPI convertToApiBean() {
         final OpenQuestionItemAPI openQuestionItemAPI = new OpenQuestionItemAPI();
@@ -43,12 +45,14 @@ public class OpenQuestion extends Item implements ExportableItem {
         return openQuestionItemAPI;
     }
 
+    @JsonIgnore
     @Override
     public List<String> getExportAnswersLabels(List<String> answers) {
         // On n'a pas de code, la réponse est directement la valeur à exporter.
         return answers;
     }
 
+    @JsonIgnore
     @Override
     public String getExportQuestionLabel() {
         if (StringUtils.isBlank(shortLabel)) {