Pass callingPackage in UserLifecycleTest#startApp

Calling IActivityTaskManager#startActivity requires the callingPackage
to be set correctly as of ag/8668823, otherwise a SecurityException is
thrown.

Bug: 138095678
Test: Enable multi-user by declaring the
      "android.software.managed_users" feature and setting
      "config_multiuserMaximumUsers" to greather than 1. Then:
      `atest android.multiuser.UserLifecycleTests#managedProfileUnlockAndLaunchApp`

Change-Id: Iab7cf0198a02a976ef5c54e4b87fb127aa7eac9a