Add Null Cipher Get/Set to Telephony Service

PhoneInterfaceManager will set a SharedPreference and
trigger an update for each Phone instance, which corresponds
to an update for each modem on the device.

Radio Network HAL 2.1 or greater is enforced, as are relevant
read and modify permissions.

Bug: 260844152
Test: atest PhoneInterfaceManagerTest
Change-Id: I28ed69883249e94e02fb371cd2e0ba7e402a376f
2 files changed