Reduce Repetitive Calls to TelephonyManager From Telephony2gUpdater

Only update allowed network status for a subId if one of the following
conditions is met:

1. The subId is newly added.
2. The DISALLOW_CELLULAR_2G user restriction changes, in which case all
   subIds are updated.

Also fixes a bug in which hidden subscriptions were not being updated.

Test: atest Telephony2gUpdaterTest
Test: Manual testing w/ TestDPC app and inserting and removing SIM
Bug: 263869683
Change-Id: I9a59046fbfb5da2525e208ea7e26973fa62792e9
3 files changed