[Provider Model] Internet Panel UI update

- Add gear icon to connected non-carrier network

- Update "View airplane mode networks" wording

- Update "Turn off airplane mode" wording

- Check WiFi disable to show airplane mode message

- Screenshot
  https://screenshot.googleplex.com/BRjcKyMaMS4ujYN

Bug: 173413889
Test:
- Manual Test
- adb shell am start -a
android.settings.panel.action.INTERNET_CONNECTIVITY

Change-Id: Icf7b77e514cffa68cf103dbc9e7df93d58f9f762

src/com/android/settings/wifi/slice/WifiSlice.java

@@ -183,7 +183,7 @@ public class WifiSlice implements CustomSliceable {
 
     private IconCompat getEndIcon(WifiSliceItem wifiSliceItem) {
         if (wifiSliceItem.getConnectedState() != WifiEntry.CONNECTED_STATE_DISCONNECTED) {
-            return null;
+            return IconCompat.createWithResource(mContext, R.drawable.ic_settings_24dp);
         }
 
         if (wifiSliceItem.getSecurity() != WifiEntry.SECURITY_NONE) {