[FUI06] Stop using NetworkInfo in NetworkState from external callers

This is achieved by:
  1. Use legacy network type inside NetworkState to replace the
     needs of referencing NetworkInfo.getType().
  2. Let getAllNetworkState only return networks with isConnected()
     equals true. This allows callers such as NPMS or NSS does not
     have to reference to NetworkInfo.isConnected().

Test: atest FrameworksNetTests NetworkPolicyManagerServiceTest
Bug: 174123988
Change-Id: I1c4eb08d18ca973eb8f41d06258872eabc0006b8