Bugfix: MetricType was not initialized in io.milvus.orm.iterator.SearchIterator#executeNextSearch (#881) (#888)

Signed-off-by: PiercarloSlavazza <p.slavazza.github@explurimis.it>
Co-authored-by: Piercarlo Slavazza <p.slavazza@elibra.eu>

src/main/java/io/milvus/orm/iterator/SearchIterator.java

@@ -229,6 +229,7 @@ public class SearchIterator {
                 .withOutFields(searchIteratorParam.getOutFields())
                 .withRoundDecimal(searchIteratorParam.getRoundDecimal())
                 .withParams(JacksonUtils.toJsonString(params))
+                .withMetricType(MetricType.valueOf(searchIteratorParam.getMetricType()))
                 .withIgnoreGrowing(searchIteratorParam.isIgnoreGrowing());
 
         if (!StringUtils.isNullOrEmpty(searchIteratorParam.getGroupByFieldName())) {