Initialization causes IMS to deregister

When the ImsPhone is initialized, it calls
ImsManager#updateImsServiceConfig before the CarrierConfig
has loaded. This causes telephony to signal the radio to
deregister IMS and then register again once the CarrierConfig
is loaded.

This change removes the updateImsServiceConfig calls during
initialization.

Bug: 37763722
Test: Telephony unit tests and analyzing logs
Change-Id: I762ba2a23cb0cae88af8256d3903a6852cface68