Add test_load_collection_without_flush (#5818)

Signed-off-by: zhenshan.cao <zhenshan.cao@zilliz.com>

tests/python_test/collection/test_load_collection.py

@@ -198,7 +198,7 @@ class TestLoadCollection:
             message = getattr(e, 'message', "The exception does not contain the field of message.")
             assert message == "describe collection failed: can't find collection: %s" % collection
 
-#     @pytest.mark.tags(CaseLabel.tags_smoke)
+    @pytest.mark.tags(CaseLabel.tags_smoke)
     def test_load_collection_without_flush(self, connect, collection):
         """
         target: test load collection without flush