Put all operations of MultiSimSettingController in main looper.

Make all operations of MultiSimSettingController handled asynchronous
in Phone process's main looper. This will:
1) Remove the possible deadlock between it and DataEnabledSettings.
2) Remove the race condition between it and SubscriptionInfoUpdater.

Bug: 130687339
Test: unittest and manual
Change-Id: I4b14b154ff14faf677846e2e2e12c1da9cd8261f