Remove CarUserManagerHelper #getCurrentForegroundUserInfo and #getCurrentForegroundUserId

Removes these two APIs in favor of using UserManager APIs and
ActivityManager.getCurrentUser().

Bug: 131776619
Test: atest CarServiceUnitTest
Test: atest CarServiceTest
Test: atest CarSettingsRoboTests
Change-Id: I9dd4b5757d18946e3670a380cf504eb267f755b2
2 files changed