Layer names generated by upload/worker contain ids, are too long

[fm3]

We should have a look end-to-end at what is causing the long layer names when uploading tiffs which are then converted by the worker convert_to_wkw job.

I think wk moves stuff around into temporary directories. The worker might then take the layer name from those directory names, which is not ideal. But that’s just a theory, should be checked.

Not sure if the fix will happen on wk or voxelytics side, but I’m opening the issue here for now.