workerutil: errors exceeding max retries are not marked failed

Created by: coury-clark

Turns out the issue here is that there was a bug in the logic to mark records terminally failed after exceeding their max retries. It is semantically correct that we display errored records as pending, since they will be retried and still count as part of the overall queue.

Originally posted by @coury-clark in https://github.com/sourcegraph/sourcegraph/issues/24203#issuecomment-903012439