Report Media Upload Failure

The browser says an upload did not make it, and why.

A failed PUT to Google Cloud Storage never touches our servers, and the bucket keeps no access log, so until this existed the evidence for "the video would not upload" was a student's message to their teacher. One WARNING line per failure, with the stage, the reason, how far it got and which client: enough to tell a dead connection from a refused file next time. Writes nothing else; the caller is the token's user.