Add @TestApi to inject driving state.

This API is intended for helping testing driving state and UX
restrictions.

Bug: 120044659
Test: ats-tradefed run ats -m AtsCarTests --test com.google.android.car.ats.CarUxRestrictionsManagerTest
Change-Id: Iea3bc977fb6765a322d72b651d609dd4c35e3ae9
4 files changed