[sat] use emergency calls text when satellite icon should show

Before this change, DeviceBasedSatelliteViewModel.carrierText only
emitted valid strings when the satellite repository reported that it was
On or Connected. This means that there were cases where the icon would
show (thus indicating satellite was _maybe_ possible), and there would
be no associated carrier text.

This change attempts to be minimal, and assumes that setting the carrier
text (which is propagated through CarrierTextManager) in this case, it
will properly show up in QS and lock screen.

Bug: 342477289
Test: manually by modifying code to put the device into the correct
state
Test: DeviceBasedSatelliteViewModelTest
Flag: NONE bugfix

Change-Id: Ic03982921704cf8452b20162058d7c7a16423c7d