Use Activity.getActivityToken to align with mr2

Context.getActivityToken is introduced since O.
To align with MR2 and avoid unnecessary merge conflict,
pass the activity token from activity to controller.

Test: 1. make RunSettingsRoboTests
      2. Manual Test
      	a. Start SET_NEW_PASSWORD intent in user 0, set password.
         	User 0 password is set.
      	b. Start SET_NEW_PASSWORD intent in work profile, set password.
         	work profile password is set.

Bug: 32959373
Change-Id: I8577752d446a7c395ad30417f8c0c832f951d7b3