AOD: When prox covered disable touch during pulse instead of aborting

Fixes a UX issue where covering the prox would abort dozing. This
was done to prevent falsing and save power, but in practice results
in a frustrating experience when the proximity sensor is covered
transiently when reaching for the device.

Instead, just ignore touch while the sensor is covered.

Change-Id: Id70f8605c6c7a37288a383d587025bb9b4191b42
Fixes: 64007762
Test: Trigger AOD2, cover sensor. Verify phone stays on but double tap does nothing.