Report negative proximity if we lose the prox sensor

Bug: 265612914
Test: Start a phone call, cover the prox sensor so the screen turns off, perform a state transition so that we no longer have a prox sensor, see that the screen turns back on.
Test: atest DisplayPowerControllerTest
Test: atest DisplayPowerController2Test
Test: atest DisplayPowerProximityStateControllerTest
Change-Id: I01e7c8ad2a5dc8fb9e01aa6e9622d2b4dbd812df