Identify incomplete processing in OQC server helper

[oarnold-oqc]

json null previously matched against c++ NULL 0. This allowed the future to terminate and fetch results before processing had finished.

Description

[copy-pr-bot]

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[bmhowe23]

/ok to test

Command Bot: Processing...

[github-actions]

CUDA Quantum Docs Bot: A preview of the documentation can be found here.

[bmhowe23]

Thanks, @owen-oqc. Do you think this change can explain these two nightly integration test failures?

1. https://github.com/NVIDIA/cuda-quantum/actions/runs/6346699077
2. https://github.com/NVIDIA/cuda-quantum/actions/runs/6515196721

The error for those runs looked like this:

[2023-09-29 03:28:12.135] [info] [OQCServerHelp.cpp:267] Null results received; fetching detailed error message here: https://sandbox.qcaas.oqc.app/tasks/225a5665-264f-4730-8400-e1cb10c3fc07/error
terminate called after throwing an instance of 'std::runtime_error'
  what():  OQC backend error message: {"task_error":null}
/__w/_temp/54c4d008-0960-46fa-b317-d7d26c92b688.sh: line 10:  5857 Aborted                 (core dumped) ./a.out

[oarnold-oqc]

Thanks, @owen-oqc. Do you think this change can explain these two nightly integration test failures?

1. https://github.com/NVIDIA/cuda-quantum/actions/runs/6346699077
2. https://github.com/NVIDIA/cuda-quantum/actions/runs/6515196721

The error for those runs looked like this:

[2023-09-29 03:28:12.135] [info] [OQCServerHelp.cpp:267] Null results received; fetching detailed error message here: https://sandbox.qcaas.oqc.app/tasks/225a5665-264f-4730-8400-e1cb10c3fc07/error
terminate called after throwing an instance of 'std::runtime_error'
  what():  OQC backend error message: {"task_error":null}
/__w/_temp/54c4d008-0960-46fa-b317-d7d26c92b688.sh: line 10:  5857 Aborted                 (core dumped) ./a.out

Yes exactly this

[bmhowe23]

Yes exactly this

Great! If you merge the latest from main into your branch, we can get this merged after that.

[bmhowe23]

/ok to test

Command Bot: Processing...