When a download is canceled, finishes, or is interrupted (e.g. loss of network connection) we finish the KJob to remove it from notification area.
However, when a job was interrupted and is then resumed, the download ID is reused by the browser and we only get sent updates for a job we no longer have.
When we get a change event from interrupted to in_progress just pretend a new download was created and carry on as normal.

BUG: 401038

• Started a download, cut my network, waited for it to fail, resumed it: now got a download job in notification area, previously nothing would happen
• Canceling and restarting the download still works fine
• Starting a new download still works fine