Use exact flag in uhubctl, allowing a USB 2.0 device to continue to work even when it's 3.0 counterpart is off

Turns out a port can only be disabled if USB 2 and USB 3 ports are turned off. This makes it too difficult as there is no context of USB 2.0 or USB 3.0 in the Web GUI. By using exact, I can turn off the USB 3.0 port, but still keep USB 2.0 on, allowing DACs to work.