Fix Wi-Fi tips disappeared issue in airplane mode

- The Wi-Fi state will not be called back in the airplane mode, need to
call onWifiStateChanged() to update the initial state of the UI.

- Screenshot:
  https://screenshot.googleplex.com/8XJXAGTS5FetGQi

Bug: 173179150
Test: manual test
make RunSettingsRoboTests ROBOTEST_FILTER=WifiSettingsTest

Change-Id: I6d9eae26d6def3bff942f8b01e2ddb453327a7de

src/com/android/settings/wifi/WifiSettings.java

@@ -346,6 +346,10 @@ public class WifiSettings extends RestrictedSettingsFragment
         if (intent.hasExtra(EXTRA_START_CONNECT_SSID)) {
             mOpenSsid = intent.getStringExtra(EXTRA_START_CONNECT_SSID);
         }
+
+        // After rebooting the device, the Wi-Fi state will not be called back in the airplane
+        // mode, need to call onWifiStateChanged() to update the initial state of the UI.
+        onWifiStateChanged();
     }
 
     @Override