User restriction to block adding SIMs

Adds a flag for the eSIM project, and define user restriction
that will block addition of new SIMs to the device.

Next steps:
- Settings policy transparency
- Programatically disable physical SIMs when the restriction is set

Test: TestDPC, set restriction, observe actions blocked in settings

Change-Id: Id89a3c19a0c8795da729082171977c5170167f9f
Bug: 316325560