[Provider Model] Adjust slice title and subtitle

- Show "Airplane mode" title when airplane mode is enabled

- Remove "Airplane mode is on" subtitle

- Show "Wi-Fi is turned on" subtitle when both airplane mode and Wi-Fi
is enabled

- Remove the function related to isApmNetworksAvailable()

- Screenshot:
  https://screenshot.googleplex.com/6X9nzmXRCUfw4Lp
  https://screenshot.googleplex.com/6jQryMjU2yDDpmM

Bug: 181858434
Test: manual test
atest -c InternetConnectivityPanelTest \
         InternetPreferenceControllerTest \
         InternetUpdaterTest

Change-Id: I84e5d4c60ed91d58443b27c35286a84bf72ac173

src/com/android/settings/network/InternetUpdater.java

@@ -73,9 +73,9 @@ public class InternetUpdater implements AirplaneModeEnabler.OnAirplaneModeChange
         default void onAirplaneModeChanged(boolean isAirplaneModeOn) {};
 
         /**
-         * Called when airplane mode networks state is changed.
+         * Called when Wi-Fi enabled is changed.
          */
-        default void onAirplaneModeNetworksChanged(boolean available) {};
+        default void onWifiEnabledChanged(boolean enabled) {};
     }
 
     /**
@@ -157,9 +157,8 @@ public class InternetUpdater implements AirplaneModeEnabler.OnAirplaneModeChange
         @Override
         public void onReceive(Context context, Intent intent) {
             fetchActiveNetwork();
-            if (mListener != null && mAirplaneModeEnabler.isAirplaneModeOn()) {
-                mListener.onAirplaneModeNetworksChanged(
-                        mWifiManager.getWifiState() == WifiManager.WIFI_STATE_ENABLED);
+            if (mListener != null) {
+                mListener.onWifiEnabledChanged(mWifiManager.isWifiEnabled());
             }
         }
     };
@@ -272,10 +271,9 @@ public class InternetUpdater implements AirplaneModeEnabler.OnAirplaneModeChange
     }
 
     /**
-     * Return ture when the APM networks is available.
+     * Return ture when the Wi-Fi is enabled.
      */
-    public boolean isApmNetworksAvailable() {
-        return mAirplaneModeEnabler.isAirplaneModeOn()
-                && (mWifiManager.getWifiState() == WifiManager.WIFI_STATE_ENABLED);
+    public boolean isWifiEnabled() {
+        return mWifiManager.isWifiEnabled();
     }
 }