[Wi-Fi] Add STA+AP information in Hotspot & tethering footer

Use WifiManager#isStaApConcurrencySupported() to check if a
device supports STA+AP and shows the footer information.

Bug: 121328949
Test: make RunSettingsRoboTests ROBOTEST_FILTER=TetherSettingsTest
      make RunSettingsRoboTests ROBOTEST_FILTER=WifiTetherFooterPreferenceControllerTest
Change-Id: I3446abb5cc9cdf76da8d17f5de31bd65715c165c
diff --git a/src/com/android/settings/AllInOneTetherSettings.java b/src/com/android/settings/AllInOneTetherSettings.java
index a15ad1f..251d135 100644
--- a/src/com/android/settings/AllInOneTetherSettings.java
+++ b/src/com/android/settings/AllInOneTetherSettings.java
@@ -56,6 +56,7 @@
 import com.android.settings.wifi.tether.WifiTetherApBandPreferenceController;
 import com.android.settings.wifi.tether.WifiTetherAutoOffPreferenceController;
 import com.android.settings.wifi.tether.WifiTetherBasePreferenceController;
+import com.android.settings.wifi.tether.WifiTetherFooterPreferenceController;
 import com.android.settings.wifi.tether.WifiTetherPasswordPreferenceController;
 import com.android.settings.wifi.tether.WifiTetherSSIDPreferenceController;
 import com.android.settings.wifi.tether.WifiTetherSecurityPreferenceController;
@@ -71,7 +72,7 @@
  * Displays preferences for all Tethering options.
  */
 @SearchIndexable
-public final class AllInOneTetherSettings extends RestrictedDashboardFragment
+public class AllInOneTetherSettings extends RestrictedDashboardFragment
         implements DataSaverBackend.Listener,
         WifiTetherBasePreferenceController.OnTetherConfigUpdateListener,
         SharedPreferences.OnSharedPreferenceChangeListener {
@@ -304,6 +305,8 @@
                 new WifiTetherSecurityPreferenceController(context, listener));
         controllers.add(
                 new WifiTetherAutoOffPreferenceController(context, KEY_WIFI_TETHER_AUTO_OFF));
+        controllers.add(
+                new WifiTetherFooterPreferenceController(context));
 
         return controllers;
     }