Prevent crash in AccountManager after profile removal.

When user profile is removed AccountManagerService.purgeUserData may be
called after a delay. Until it happens other methods may try to access
database for a removed profile which causes a crash.

Bug: 281980345
Test: N/A
Change-Id: Idb9840a5b9f9fdc84516149066cbb2a945c083a7
(cherry picked from commit 1fb0fb38)