When working on #477 I noticed that there is no task progress, when zipped WOS files are uploaded.

This is because there is no estimate on the backend of the number of documents, there's only 'succeeded: 300, remaining: 0'. So the frontend thinks that job is done and doesn't render it. We should fix 'remaining' and if it's not possible to estimate the number of docs that are remaining, at least index by file count in the zip archive.