Evaluate auto data switch upon hangup voice call

Upon hangup voice call, reevalute whether we should auto data switch.
Also clean up the dataEnableChanged event interacting with voice call: Before the change, if data is disabled during call, the expected behavior is that user loses access to data immediately during call, but the previous behavior is that user still has data access.

Fix: 262335341
Test: atest + toggle mobile data during call

Merged-In: Iabfa73c70e344b4f49950a9a495edf6f00f8b144
Change-Id: Iabfa73c70e344b4f49950a9a495edf6f00f8b144