Setting parameter values on submit_activity_answer in VPAL engine driver

[kunanit]

The submit_activity_answer() method in VPAL engine driver tries to use learner and activity attributes of sequence_item instance directly, but learner is not a model field of sequence_item, and activity attribute is a model instance.

bridge-adaptivity/bridge_adaptivity/module/engines/engine_vpal.py

Line 142 in d3bf682

payload = self.fulfill_payload(instance_to_parse=sequence_item)