Remove migrated config_carrier_wfc_ims_available

config_carrier_wfc_ims_available has already been migrated to
CarrierConfig. This commit removes reference to this carrier config from
non-prebuilt config files.

Bug: 29873049
Change-Id: I74a3296494377e771d5d451db62c554485bbeb98

undelete config_device_wfc_ims_available

Fix accidental removal of config_device_wfc_ims_available and correctly
remove config_carrier_wfc_ims_available

Bug: 29873049
Change-Id: If47b743547b55e2ff3daf0357372a5d398c8b6ab