Apply slicing capabilities before connected

Slicing related capaiblities used to be set from the traffic
descriptors from modem after connected. This causes network
requests unexpectedly detached in connecting state. Fixed by
applying the capability from data profile's traffic descriptor.
This will grant the slicing capabilities while the data network
is still in connecting state.

Fix: 228107174
Test: atest DataNetworkTest
Change-Id: Ia15ce221847ce9cc00aa5d858d00f69d2dd077f9