[Telephony] getDataNetworkType() uses incorrect subid

When data network type is queried without sub id, network type
on default voice sub is being returned. Instead it should return
network type value on dds sub.
Fix is to replace getDefaultSubscritpion with getDefaultDataSubId

Bug: 145683023
Test: make
Change-Id: Ie7ba466f308d5c16a14287228b3036c5bf187c07
1 file changed