refactor updateIccId for msim

1. updateIccId for each slot in parallel.
today we are waiting for both sim iccid loaded and then update
simInfo db, assigning subId and update internal slotId-to-subId
altogether.e.g,
1. SIM loaded
2. no subId
3. send sim loaded event with invalid subId
Change to do update for each slot independently, making sure we have
valid subId before broadcasting sim ready.

2. clean up updateIccId API logics
Bug: 120686729
Test: Manual test under msim configurations
Change-Id: I8f0d42905ea59817983d17dbf558a70904008fa3