Create CallStateRepository.isInCallFlow

Which will emit true if any active sub is in call.

And also create SubscriptionActivationRepository to use isInCallFlow.

Bug: 336209156
Test: manual - on MobileNetworkSwitchController
Test: unit test
Change-Id: I75460bf17961349557ac1e19e7f6b15249f3d7b0
9 files changed