Change CarrierRoamingNtnListener to public API.

Bug: 371872603
Bug: 433512598
Test: atest
API-Coverage-Bug: 421407882
Flag: com.android.internal.telephony.flags.telephony_satellite_apis
Change-Id: If87727a976c5d2e846ba9c8b80581382e3d619c9
4 files changed