[Catalyst] SIMs screen migration

- Add a flag for the migration
- Add the skeleton of the screen

Test: atest MobileNetworkListScreenTest
Bug: 368355368
Flag: com.android.settings.flags.catalyst_mobile_network_list
Change-Id: I9d5d57b78d8f2c7d2bc6fd02e402fcdaf5b97bdf
4 files changed