[Settings] Refactor of Wifi Calling part

Refactor of Wifi Calling to avoid accessing hidden APIs.
This includes the following cherry-picks on the corresponding files:
I455685eb26df69d929ff3ed3c26ce84aa5f6b1f8
I1a67db80b114a438afda7d45af90e54af38703c3
Idd4935a6d8ceed77c15e90f96781014d1940a427
Ia5179ee1a23f054899bc74c796542bae40cdc8d5
I57c91a095fc4d454d92e8d78e0b647b4f098c6a3
I8a09264f83b9fc4fce3f79ec3aeb6ae757b004e4
I68462368669b81e10d09bbb93e74e23ea9a1f446
I9c54eb63a0df3fde38965ee7e2ae46cc1b7efd47
I0d5dcfc33b0bddacf059d1fb9af559646e32e68a
I45977c850977be84c0dc1f6461e68a1941efc1a2
I46c047359257ddd5cb3e331add4856b01c5c9739
I35246811d3e01d0b2ca197e9a1ed7081691cd982

Bug: 140542283
Test: build pass
Change-Id: I2cddeefb7cc5f1b2060e572a73560f7cd6204d0b