[UX] Windows .msi installer should update existing installation of cloudflared

If you run the cloudflared .msi installer on a system which already has an older version of cloudflared installed on it, the installer will exit with the following error message:


The typical behavior of Windows software installers is to update the existing installation of the software instead of manually requiring the user to first uninstall the previous version. It would improve the UX of updating cloudflared if the installer were to simply update an existing installation of the software as well.