Removed excludePreCreated from internal getUsers() methods.

Pre-created users are deprecated and shouldn't be returned on any
getUsers() method anymore.

Test: atest FrameworksMockingServicesTests --test-filter=".*UserManagerServiceMockedTest#testGetUsers.*"
Flag: EXEMPT refactoring
Fix: 419586881

Change-Id: Id0cba5f4873740db050e0a524e1ed7efb2016f04