Fix: Fixed crash that would occur at the start of a file operation if Explorer wasn't running

[hishitetsu]

I cannot reproduce the crash myself, but it seems to occur in environments where explorer.exe is not running as a shell (e.g. RemoteApp).

Resolved / Related Issues

• Were these changes approved in an issue or discussion with the project maintainers? In order to prevent extra work, feature requests and changes to the codebase must be approved before the pull request will be reviewed. This prevents extra work for the contributors and maintainers.
  Closes Bug: ITaskbarList2.HrInit System.NotImplementedException #13664

Validation
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[yaira2]

LGTM