Use user WFC setting instead of checking WFC service status

Check if WFC has been enabled by user instead of checking if
IMS over wifi is enabled. This covers the case of VT offload,
where user has disabled WFC but call is on wifi.

Test: Manual
Bug: 38459634
Change-Id: I27831be65d8d05e7e26a60ee6b2de1d8bfbf7a03
1 file changed