Communal profile is always keyguard-unlocked

The Communal Profile is a profile with no parent, and is expected to
be visible over any user's lockscreen. By its very nature, it is
therefore never considered locked. If something (such as
GrantPermissionsActivity) asks whether the device is locked for this
user, it should therefore be told no.

We accomplish this by making sure that unsecured profiles (like the
communal profile) are set to unlocked, just like how managed profiles
were.

Bug: 311073113
Flag: ACONFIG android.multiuser.support_communal_profile DISABLED
Test: atest CtsAppTestCase:asndroid.app.cts.KeyguardManagerStatusTest
Test: Manually confirmed that permissions can be accepted, despite it
requiring a keyguard check

Change-Id: Iffe150cfb6ff65a9c870eafe5b3a2903638cfaf3