[DO NOT MERGE] Add FLAG_SECURE for ChooseLockPassword and Pattern

Prevent ChooseLockPassword and ChooseLockPatten being projected to
remote views, add FLAG_SECURE for these screens.

Bug: 179725730
Test: Check these 2 screens not projected to chromecast
Test: robo test for SetupChooseLockPatternTest ChooseLockPatternTest
      SetupChooseLockPasswordTest ChooseLockPasswordTest
Change-Id: I7449a24427c966c1aa4280a7b7e7e70b60997cca
Merged-In: I7449a24427c966c1aa4280a7b7e7e70b60997cca
(cherry picked from commit 98239c0d)