Update the carrier service UID when onCarrierServiceChanged

Tests show that when the carrier service package changes, sometimes
neither onCarrierPrivilegesChanged is called nor the
ACTION_MULTI_SIM_CONFIG_CHANGED broadcast is sent.
Because updating synchronously can be done at any time, it's a
strict improvement to also do it onCarrierServiceChanged.

Test: CarrierPrivilegeAuthenticatorTest
Change-Id: I9525bfe074dd686720d50e19be15529b248e9dbb