Fix DO provisioning for auto

* Use system userId instead of calling userId
for auto.
* Fixed a bug in the non required apps removal logic
that would cause provisioning to fail if the packages
returned from overlayPackagesProvider are not all installed
on the user.

Bug: 179735139
Test: atest  DeviceOwnerTest#testDeviceOwnerProvisioning
Change-Id: Ic26a3b503b06b301f36f47b9b40c0b9bffbf2a5b