ADSC: evaluate auto data switch on carrier config change

The patch fixes the issue that auto data switch for OPPT is not
immediately evaluated when the carrier enables or disables the feature
through carrier config.

ADSC used to depend on DataConfigManager to monitor and update the
carrier config for OPPT switch. When carrier config changed, DCM doesn't
proactively inform ADSC and the switch evalution occcurs only from other
event follows (e.g. subcription change).

Although DCM can provide carrier config callback for ADSC to monitor,
the per-slot callback makes the management unnecessarily complicated. So
this change let ADSC minitor carrier config change to simplify the logic.

Bug: 436856439
Test: atest AutoDataSwitchControllerTest
Test: ADSC feature test for OPPT
Flag: com.android.internal.telephony.flags.monitor_carrier_config_change_for_auto_data_switch
Change-Id: I02ae8ae15dddd652e4786d9ab231e29f37d2ad51