simplify material copying

GUI/Model/Job/JobModelFunctions.cpp

@@ -131,11 +131,8 @@ void GUI::Model::JobFunctions::setupJobItemSampleData(JobItem* jobItem,
     // copy used materials into material container
     for (auto* itemWithMaterial : sampleItem->itemsWithMaterial()) {
         auto* material = itemWithMaterial->materialItem();
-        if (!jobItem->materialItems().findMaterialItem(material->identifier())) {
-            auto* materialCopy = jobItem->materialItems().insertCopy(*material);
-            materialCopy->setIdentifier(material->identifier());     // insertCopy() doesn't do this
-            materialCopy->setMaterialName(material->materialName()); // insertCopy() doesn't do this
-        }
+        if (!jobItem->materialItems().findMaterialItem(material->identifier()))
+            jobItem->materialItems().addMaterial(new MaterialItem(*material));
     }
 }