[Settings] Replace getSimCount() API

Change design of monitor change in Settings.Global.MOBILE_DATA and
Settings.Global.DATA_ROAMING in order to avoid from accessing
getSimCount().

Bug: 144251589
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=RoamingPreferenceControllerTest
Change-Id: If50c57e7c1b27f9a0baf2bd46cc0930e0a0be2bd
4 files changed