Update notification redacted state for profile.

Put back two missing bits of logic relevant for managed profiles:
1. Update user's public mode when work challenge is unlocked.
2. Update notifications when public mode changes.

This ensures that redacted notifications become readable again
when work profile challenge is unlocked.

Test: manual, using Hangouts in a profile with separate lock
Bug: 128896361
Change-Id: I0aad2df233c8e3f2820dbe69230ba0897ab45ab1