Restrict WiFi network connection (Internet Panel)

- Use StandardWifiEntry#canConnect() to determine if the network should
  be disabled or not.

- Disabled WiFi network if it cannot connect.

- If WiFi network is connected or saved network, leave it enabled to
  disconnect or configure.

- See the result screenshot in b/203168943#comment14

Bug: 203168938
Bug: 203168943
Test: manual test
atest -c InternetAdapterTest \
         InternetDialogControllerTest \
         InternetDialogTest

Change-Id: I7d488bf0298d3ee6c8e315fbab0ea492e684efd1