Handling the MTurkUnit with no message data

[mojtaba-komeili]

Patch description
After the recent changes to Mephisto, when I try to compile the data from the data collection task, there is the following error that indicates some of the MTurkUnits have no messages.

  File ".../Mephisto/mephisto/abstractions/blueprints/parlai_chat/parlai_chat_agent_state.py", line 99, in get_parsed_data
    if "WORLD_DATA" in messages[-1]:
IndexError: list index out of range

Testing steps
My data compiler ran without any issue after these changes. It just produced a couple of warnings that indicated the units with missing data.

[mojtaba-komeili]

@JackUrb there might be something missing on the Mephisto side that might resolve this issue for the future. But I think it is good to have this for corrupted data in general.

[JackUrb]

Adding @EricMichaelSmith as this is now breaking crowdsourcing tests.

[EricMichaelSmith]

@mojtaba-komeili Can you try pulling from master? Stephen recently merged in a PR at #3628 that should hopefully remedy the crowdsourcing test issues

[mojtaba-komeili]

@mojtaba-komeili Can you try pulling from master? Stephen recently merged in a PR at #3628 that should hopefully remedy the crowdsourcing test issues

Yeah, that solved the issue. Thanks!