Update GrpcRequestHandler.cpp (#2069)

Signed-off-by: Npengjian05 <pengjian05@baidu.com>
Co-authored-by: Npengjian05 <pengjian05@baidu.com>

core/src/server/grpc_impl/GrpcRequestHandler.cpp

@@ -544,9 +544,8 @@ GrpcRequestHandler::SearchInFiles(::grpc::ServerContext* context, const ::milvus
 
     // step 3: partition tags
     std::vector<std::string> partitions;
-    for (auto& partition : search_request->partition_tag_array()) {
-        partitions.emplace_back(partition);
-    }
+    std::copy(search_request->partition_tag_array().begin(), search_request->partition_tag_array().end(),
+              std::back_inserter(partitions));
 
     // step 4: parse extra parameters
     milvus::json json_params;