 Add extra check in device ID extraction
 Add extra check in device ID extraction

Some devices (especially mine, the path is ok) is not possible to read the "device id" stored in steam.uuid.xml.
changes: GetDeviceID() now returns null and use Regex to read "device id".
This pull prevents save the string "ERROR" as device id.
Jessecar96/SteamDesktopAuthenticator,sebastianbassen/SteamDesktopAuthenticator