Notify WifiManager of interface state changes

Test: as follows
    - built
    - flashed
    - booted
    - "runtest frameworks-net" passes
      (except for an unrelated IpConnectivityMetricsTest error)
Bug: 31466854
Bug: 32163131
Change-Id: I702ea79eb2c02604761e4e1ebcd5f9e445178efb