Assume sensors perform prox check

Assume that doze sensors will be prox gated.
Not doing so would be a bad idea anyway since the device would wake
up way more often than it should and drain battery.

Another improvement on this CL is that regular DozeSensors prox
checks are trying to use a binned brightness sensor instead.

Fixes: 138765669
Test: atest DozeSensorsTest DozeTriggersTest
Test: single tap from AOD (observe no re-registration of lift)
Test: 'reach' from AOD (observe no re-registration of lift)
Test: receive notification with prox covered or unobstructed
Change-Id: I1961ff9b16480ba1a60c397570494dd7acb4802d