Migrate all AlertDialogs to AndroidX version

This CL only changed AlertDialog imports.
So, reviewer can review it easily.

Change-Id: I097bc44394195b14287f4f920c570ac8653f356a
Fixes: 111413092
Test: This CL can't pass Robo test.

src/com/android/settings/RadioInfo.java

@@ -20,7 +20,6 @@ import static android.net.ConnectivityManager.NetworkCallback;
 import static android.provider.Settings.Global.PREFERRED_NETWORK_MODE;
 
 import android.app.Activity;
-import android.app.AlertDialog;
 import android.app.QueuedWork;
 import android.content.ComponentName;
 import android.content.Context;
@@ -91,6 +90,8 @@ import java.net.HttpURLConnection;
 import java.net.URL;
 import java.util.List;
 
+import androidx.appcompat.app.AlertDialog;
+
 public class RadioInfo extends Activity {
     private static final String TAG = "RadioInfo";