Finish time on requests for Unknow files

[ArturU043]

Description
Entering a wrong rucio DID causes the transformation request to enter the complete status with no finish time value.
The web dashboard will pin these requests on top if sorted by Finish(desc) (default)

This could happen if there are typos and it clutters the dashboard when there are multiple

A finish time value and a special status should be attributed to these requests.

Example screenshot