Pending VM download progress is not visible if many VMs in the list

The in-progress VMs should be more easily discoverable if there are lots of VMs already in the list. On my machine it is only because of the setting to always show scroll bars that I can see there is a new item. (scroll bar shrinks)

I propose the pending VMs should be overlaid on the list:

No files or tests are named. Start by locating the VM list and the UI that displays pending downloads, then inspect how new list items are inserted. Done means pending VMs remain clearly discoverable when many VMs are already present, matching the proposed overlay behavior.

Written by the indexing model from the issue text.