To avoid crash IllegalStateException

Bug: 308855978
Test: [pass]make RunSettingsRoboTests ROBOTEST_FILTER=NetworkProviderSettingsTest
Change-Id: Ia0a1cbe0326e63b878c3fe7797ca47e25ccc16d4
diff --git a/src/com/android/settings/network/NetworkProviderSettings.java b/src/com/android/settings/network/NetworkProviderSettings.java
index b4de224..d5bc2af 100644
--- a/src/com/android/settings/network/NetworkProviderSettings.java
+++ b/src/com/android/settings/network/NetworkProviderSettings.java
@@ -845,8 +845,10 @@
             return;
         }
 
-        // update the menu item
-        requireActivity().invalidateMenu();
+        if (isAdded()) {
+            // update the menu item
+            requireActivity().invalidateMenu();
+        }
 
         switch (wifiState) {
             case WifiManager.WIFI_STATE_ENABLED:
@@ -1480,8 +1482,10 @@
     @Override
     public void onAirplaneModeChanged(boolean isAirplaneModeOn) {
         updateAirplaneModeMsgPreference(isAirplaneModeOn /* visible */);
-        // update the menu item
-        requireActivity().invalidateMenu();
+        if (isAdded()) {
+            // update the menu item
+            requireActivity().invalidateMenu();
+        }
     }
 
     /**