[SB] Always check underlying wifi networks regardless of transport type.

If a user has VPN over W+ (aka VPN over carrier merged), then the main
network capability transports are WIFI|VPN, but we still need to fetch
the underlying network info to correctly show W+ in the status bar and
quick settings tile.

Previously, we only checked underlying network info if the transports
had CELLULAR. This CL removes that condition.

Bug: 352162710
Flag: com.android.systemui.status_bar_always_check_underlying_networks
Test: atest ConnectivityRepositoryImplTest
Change-Id: If02befcd57ff0f43ab215950e8833ca6faa0795a