Fix ViLTE is not available when WiFi Calling is disabled

Bug: 141831293
Test: 1. Set carrier config carrier_wfc_ims_available_bool to false,
then verify Wi-Fi calling option is not shown.
      2. Set carrier config carrier_vt_available_bool to false, then
      verify video calling option is not shown.
      3. Set both carrier_wfc_ims_available_bool and
      carrier_vt_available_bool to false, then verify calling category
      is not shown.

Change-Id: Ibec13fbeb5acf1d62342286687b2ba969beb4e14