Reorient SIM processing around slot id

It was previously organized around subscriptionId as the index,
which can cause many issues with multiple sims having an invalid
subscription id of -1.

Slot Id is unique and will allow better detection of changes to
SIM state.

Fixes: 376173142
Test: atest KeyguardUpdateMonitorTest CarrierTextManagerTest
Flag: com.android.systemui.sim_pin_use_slot_id
Change-Id: Ifa246bd4738f66d8e67bcd7fe671b9fb8117e81e