Fix nullable values for incoming Github commit data

Missing commit data caused cascading failures in the request that should have resulted in just the specific commit being marked as invalid.

assigned to @cguindon and @zacharysabourin

You set us as assignees rather than reviewers :)

unassigned @cguindon and @zacharysabourin

requested review from @zacharysabourin and @cguindon

The downstream code already handles null values as rejected commits, so adding the nullable values and handling NPEs was all that's needed to get this working. I could have done a more involved check but it would have been annoyingly verbose for each check

approved this merge request

mentioned in commit 86aae94c

merged