Fix recent change breaking effects with jobs (like motion tracker)

src/assets/model/assetparametermodel.cpp

@@ -89,9 +89,6 @@ AssetParameterModel::AssetParameterModel(std::unique_ptr<Mlt::Properties> asset,
             QVariant defaultValue = parseAttribute(m_ownerId, QStringLiteral("default"), currentParameter);
             value = defaultValue.type() == QVariant::Double ? locale.toString(defaultValue.toDouble()) : defaultValue.toString();
         }
-        if (value.isEmpty()) {
-            continue;
-        }
         bool isFixed = (type == QLatin1String("fixed"));
         if (isFixed) {
             m_fixedParams[name] = value;