Fix potential NPE during initialization

1) Guard TelephonyRcsService from null PersistableBundles
from CarrierConfigManager in the scenarios where we are receving
non-INVALID subIds during initialization.
2) Ensure that CarrierConfigLoader is initialized before
TelephonyRcsService needs to use it.

Bug: 266581853
Test: flash on device, ensure calls/sms/UCE works properly
Change-Id: Ia34ead1bcddedf75613a05b81c2b77861201e7b2
3 files changed