Guard getImeiForSubscriber behind new device ID requirements

TelephonyManager#getImei which invokes PhoneInterfaceManager is
already protected by the new device identifier access restrictions.
This changes applies the same access restrictions to the
PhoneSubInfoController's getImeiForSubscriber method. The previously
ignored tests in PhoneSubInfoControllerTest are also restored.

Bug: 132380377
Bug: 117781266
Test: atest PhoneSubInfoControllerTest
Change-Id: Ia71bbaddf3293e64be9159f6d58318add1f94d0b