Fix CopyAsset Action loading
Fix CopyAsset Action loading

Base permits *either* the Source or Dest file name missing and I was
emulating this incorrectly.

Also adds a fail-fast path if both are missing, which base lacks.

Arkhist/Hacknet-Pathfinder,Arkhist/Hacknet-Pathfinder,Arkhist/Hacknet-Pathfinder,Arkhist/Hacknet-Pathfinder