Send the IMS_SERVICE_UP intent when it is STATE_READY

The ImsService must send the IMS_SERVICE_UP intent when it
signals that it is in the STATE_READY state and
IMS_SERVICE_DOWN when it is STATE_INITIALIZING or
STATE_NOT_AVAILABLE.

Also, add READ_PRIVILEGED_PHONE_STATE check

Bug: 35736451
Test: Unit tests added in frameworks/opt/telephony
Change-Id: I03d4398cf7008cf8c51b78d99eb029aa99c63f62