[Wi-Fi] Show Pie+x Wi-Fi icon when a connected Wi-Fi is not default route

From Android 11, a connected Wi-Fi network may not be default route
if rating provider thinks it has bad connection quality. Framework
service will keep the Wi-Fi connection but uses other connection as
default route.

This change shows Pie+x Wi-Fi icon for a connected Wi-Fi network which
is not default route.

Bug: 163627176
Test: make RunSettingsLibRoboTests ROBOTEST_FILTER=WifiEntryPreferenceTest
      make RunSettingsLibRoboTests ROBOTEST_FILTER=com.android.settingslib.UtilsTest
Change-Id: Ia9c98db59a5eb61ae22a5e9249d1219443876e16