AOD: Fix navbar flicker when launching assistant

When reset() gets called during unocclusion, we were hiding the
keyguard even though it is still needed while dozing; instead,
reset is now actually called after dozing finishes.

Test: Trigger assistant from AOD; verify navigation bar buttons do not show
Fixes: 64164106
Change-Id: Ic29cf40ade7d3cd492723a3f859f8a7734edad93
(cherry picked from commit 7a56d1a4)