Fix mDeviceOwnerUserId locking and annotation

The following methods were mismarked as requiring the mRestrictionsLock
in commit I1f1f024199db85d4023323169441c8514ea3cc3a. The reason was because mDeviceOwnerUserId requires that lock and it wasn't always being acquired. The correct solution is to acquire that lock. The mismarked annotations can then be removed; they weren't ever obeyed anyway.

Bug: 226607885
Test: atest UserManagerServiceTest
Change-Id: I7df5dde12e5f28ed7cd9b648aad9a5373ab4d097