Remove checks of private space flags from LockSettingsService

All three of the private space related flags being checked in
LockSettingsService have been launched since AP3A, so they've been
eligible for removal for the last 6 months.  As a small step towards
removing these, remove the flag checks from LockSettingsService.

Bug: 406891344
Test: presubmit
Flag: EXEMPT removing a flag
Change-Id: I32f6e6d0c4679149d42581e54829e1273fd1b16b