HybridSearch supports full text search (#1279)

Signed-off-by: yhmo <yihua.mo@zilliz.com>

sdk-core/src/main/java/io/milvus/v2/utils/VectorUtils.java

@@ -378,7 +378,7 @@ public class VectorUtils {
             data.add(vector.getData());
         }
 
-        ByteString byteStr = ParamUtils.convertPlaceholder(data, plType);
+        ByteString byteStr = convertPlaceholder(data, plType);
         builder.setPlaceholderGroup(byteStr);
         builder.setNq(vectors.size());