[Sat] Carrier-based view model + signal

This CL does a couple of things that are all related to get the signal
showing:

1. Update the MobileIconViewModel to have two distinct "modes", based on
   whether or not the underlying subscription represents a "non
   terrestrial" network or not. This is achieved by wrapping up the
   existing "cellular" behavior in its own private subclass, and
   implementing the satellite behavior entirely additively.

2. Update SignalIconModel to be a sealed interface to make room for the
   resource-backed satellite icon in addition to the existing
   SignalDrawable icon.

3. Add `isNonTerrestrial` to the interactor so (based on a flag) it can
   expose the new field

4. Add the satellite icon calculation to the interactor

Test: MobileIconInteractorTest
Test: SignalIconModelParameterizedTest
Test: LocationBasedMobileIconViewModelTest
Test: MobileIconViewModelTest
Test: all tests in the mobile/ package
Bug: 311417356
Flag: ACONFIG com.android.internal.telephony.flags.carrier_enabled_satellite_flag DEVELOPMENT
Change-Id: I5c71e7b3dd757b17e71fcdc6b7742eba1775c244