Fix the ambient lux which did not update for blocking zone

When the display enters doze mode, it should unregister the light
sensor. It should register light sensor again when the display
state change from doze to on otherwise we will lost lux information
and then the refresh rate could not be locked.

Bug: 176018998
Test: atest DisplayModeDirectorTest
Test: no fps transition in the blocking zone when the display state change
Test: check if the lux will update when the display state change
Change-Id: Ibf2e7cb2e336c88a583f00f59abcbc9d06ec3d62
Merged-In: Ibf2e7cb2e336c88a583f00f59abcbc9d06ec3d62