file-transfer plugin fails to download a file if to ms-appdata specified file on windows

download() in file-transfer plugin expects path instead of internal URL on windows

This bug seems to be introduced with these changes to cordova-plugin-file: https://github.com/apache/cordova-plugin-file/commit/bcbeae24cd24583b790da95e0e076492eb16cd4f

All tests for download method of file-transfer plugin now fail on windows with following message:
Exception calling native with command :: FileTransfer :: download ::exception=WinRTError: The parameter is incorrect.

As per internal discussion, this line may be the cause:
https://github.com/apache/cordova-plugin-file-transfer/blob/master/src/windows/FileTransferProxy.js#L166