remove the _id fileld when get collection info (#3414)

* fix the bug of issue #3336
Signed-off-by: Ngodchen0212 <qingxiang.chen@zilliz.com>

* fix wrong test case
Signed-off-by: Ngodchen0212 <qingxiang.chen@zilliz.com>

core/src/server/grpc_impl/GrpcRequestHandler.cpp

@@ -1021,6 +1021,9 @@ GrpcRequestHandler::DescribeCollection(::grpc::ServerContext* context, const ::m
 
         response->set_collection_name(request->collection_name());
         for (auto& field_kv : collection_schema.fields_) {
+            if (field_kv.first == engine::FIELD_UID) {
+                continue;
+            }
             auto field = response->add_fields();
             auto& field_name = field_kv.first;
             auto& field_schema = field_kv.second;

tests/milvus_python_test/collection/test_get_collection_info.py

@@ -71,7 +71,7 @@ class TestInfoBase:
         res = connect.get_collection_info(collection_name)
         assert res['auto_id'] == True
         assert res['segment_row_count'] == segment_row_count
-        assert len(res["fields"]) == 3
+        assert len(res["fields"]) == 2
         for field in res["fields"]:
             if field["type"] == filter_field:
                 assert field["name"] == filter_field["name"]
@@ -173,7 +173,7 @@ class TestInfoBase:
         res = connect.get_collection_info(collection_name)
         assert res['auto_id'] == True
         assert res['segment_row_count'] == segment_row_count
-        assert len(res["fields"]) == 3
+        assert len(res["fields"]) == 2
         for field in res["fields"]:
             if field["type"] == filter_field:
                 assert field["name"] == filter_field["name"]