Duplicate File action only works on open files

[Nokel81]

Describe the bug When executing the "Duplicate File" actions from the command pallet (or more generally a keyboard shortcut) and no file is currently open (but the explorer is active and an item is selected) an error occurs saying that a file needs to be open. This also means that if you have a file open but the explorer is what is currently active you cannot duplicate the currently active selection

To Reproduce Steps to reproduce the behavior:

1. Close all files
2. Select a file in the explorer
3. Call up the command pallet and execute the file duplicate action
4. An error is displayed

Expected behavior The currently selected file/folder is duplicated

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• VSCode Version: 1.39.0
• OS Version: 10.0.17763