Handle/log video upload errors

[becky-gilbert]

Summary

We should improve the error catching/logging for video upload timeouts and other S3/uploading problems. At the very least it would be useful to log video upload errors in the experiment data, so that researchers know whether there was an uploading problem for any particular file. EFP also uses Sentry for logging. See how this is handled in EFP, and especially in this PR: lookit/ember-lookit-frameplayer#402

[becky-gilbert]

As of #196 (lookit/lookit-api#1822) the lookit-jspsych experiment stores a list of all uploads and their status in the pendingUploads array. So it should be straightforward to add this information to the jsPsych data at the end of the study.