[Sb][Mobile] Listen for service states via broadcast for subId = -1

We already have tracking for service state for any valid subscription,
via the individual `MobileConnectionRepository` classes. However, there
are cases when there is a device-based state (in this case, emergency
calls only) that can be surfaced to SystemUI via the
ACTION_SERVICE_STATE intent. In these cases, the subscription id from
the intent is -1, and can be interpreted on our end as device state.

This change adds tracking specifically for the `ServiceState` for the
subId=-1 case, and exposes the emergency calls only state to the
MobileIconsInteractor.

Follow-up CLs will use this bit to better calculate the calling state of
the device for the sake of showing satellite iconography.

Flag: EXEMPT bugfix
Bug: 339023069
Test: MobileConnectionsRepositoryTest
Test: MobileIconsInteractorTest
Change-Id: I7cc0aee2d6f579d2027ea1f0ffdc64486126664d