To avoid crash IllegalStateException

Bug: 308855978
Test: [pass]make RunSettingsRoboTests ROBOTEST_FILTER=NetworkProviderSettingsTest
Change-Id: Ia0a1cbe0326e63b878c3fe7797ca47e25ccc16d4

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

@@ -845,8 +845,10 @@ public class NetworkProviderSettings extends RestrictedSettingsFragment
             return;
         }
 
+        if (isAdded()) {
             // update the menu item
             requireActivity().invalidateMenu();
+        }
 
         switch (wifiState) {
             case WifiManager.WIFI_STATE_ENABLED:
@@ -1480,9 +1482,11 @@ public class NetworkProviderSettings extends RestrictedSettingsFragment
     @Override
     public void onAirplaneModeChanged(boolean isAirplaneModeOn) {
         updateAirplaneModeMsgPreference(isAirplaneModeOn /* visible */);
+        if (isAdded()) {
             // update the menu item
             requireActivity().invalidateMenu();
         }
+    }
 
     /**
      * A Wi-Fi preference for the connected Wi-Fi network without internet access.