UsbPortManager: Re-enable contaminant detection when port is unplugged

SystemUI disables contaminant detection when user wants to continue
using the port. Re-enable contaminant detection when the accessory
is unplugged.

Bug: 128534822
Test: Tested with the mock circuit.
Change-Id: I22a3c839264876409c68c6a3145c9fcc6278f381
1 file changed