Add NR to preferred network type combination

This add NR 5G to preferred network type and move preferredNetworkMode
from SystemApi to hidden api as we are not going to support
preferredNetworMode enum in the future.

Bug: 111453000
Test: build
Change-Id: I08a8f7bf44a62ef109583b82b22f65fd6f89c71d
(cherry picked from commit 8bcdc4cf66e9d654fa31d7c62654ff81ee04cdc6)
Merged-in: I08a8f7bf44a62ef109583b82b22f65fd6f89c71d
4 files changed