Fix deadlock between PMS and UMS

Move scheduleWritePackageRestrictions() out of holding mLock to avoid deadlock.

Symptom:

At thread 1,

PackageManagerService#snapshotComputer held mSnapshotLock ask mLock

At thread 2,

PackageManagerService#setEnabledSettings held mLock
-> scheduleWritePackageRestrictions -> UserManagerService#exists ...
--> UserManagerService#getUserInfoNoChecks ask mUsersLock of UserManagerService

At thread 3,

UserManagerService$LocalService#getProfileIdsExcludingHidden held mUsersLock
-> getProfileIdsLU -> isProfileHidden -> getUserPropertiesCopy -> hasManageUsersPermission ...
--> PackageManagerService#snapshotComputer ask mSnapshotLock

Bug: 411582851
Flag: EXEMPT bugfix
Test: atest CtsPackageInstallTestCases
Change-Id: I974719832d612249e43e837e27e9d6f64601a5fd