[SYNTH-16456] Make server result optional in Result

[Drarig29]

What and why?

The source of truth for a result is the batch and not the server result (which we poll with the /poll_results endpoint).

The server result corresponding to a batch result may happen to never be available, and in that case datadog-ci should fall back to the source of truth (the batch) instead of failing.

When such thing happens for a result, a warning log is printed (The information for result {resultId} of test {publicId} was incomplete at the end of the batch.) and the Result.result property will be undefined.

How?

• Make Result.result optional
• Update fixtures and tests

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)

[datadog-datadog-prod-us1]

Datadog Report

Branch report: corentin.girard/SYNTH-16456/make-server-result-optional
Commit report: 3a2b2d8
Test service: datadog-ci-tests

✅ 0 Failed, 1636 Passed, 0 Skipped, 1m 54.37s Total duration (1m 35.44s time saved)

[etnbrd]

Thanks for adding the comments! 🙇
Added some precision on the comment for hasDefinedResult about missing result.
Otherwise, LGTM!