title: Notification channel created with high priority has no sound
body: <p>I am trying to create a notification channel with High Priority but the channel created has "sound off" and "floating notification" is off. I am not sure if I should include any special permission to achieve it.</p>
  
  <p>I have tried creating notification channel with high priority. Have tried changing the channel id and reinstalling the app. I am trying it in a complete new application.</p>
  
  <p>// To create channel</p>
  
  <pre><code>private void createNotificatnChennal() {
          if(Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.O)
          {
              NotificationChannel chennal1 = new NotificationChannel(
                      chennal_01_id,
                      chennal_01_name,
                      NotificationManager.IMPORTANCE_HIGH
              );
  
              AudioAttributes att = new AudioAttributes.Builder()
                      .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
                      .setUsage(AudioAttributes.USAGE_ALARM)
                      .build();
  
  
              chennal1.setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION),att);
              chennal1.setDescription("Test channel one");
  
              NotificationManager manager = getSystemService(NotificationManager.class);
              manager.createNotificationChannel(chennal1);            
          }
      }
  </code></pre>
  
  <p>// display notification</p>
  
  <pre><code>    String title = "Test title";
      String body = "Test Msg";
  
      Notification notification = new NotificationCompat.Builder(MainActivity.this,chennal_01_id)
              .setSmallIcon(R.drawable.ic_icon)
              .setContentText(body)
              .setContentTitle(title)
              .setPriority(NotificationCompat.PRIORITY_MAX)
              .setCategory(NotificationCompat.CATEGORY_MESSAGE)
              .setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION))
              .setVibrate(new long[0])
              .setDefaults(Notification.DEFAULT_ALL)
              .build();
  
      notifManager.notify(1,notification);
  </code></pre>
  
  <p>I want my notification to make sound and popup at the top. </p>
  
  <p>But for now its not making sound and doesn't popup for version >= 8.0,
  and for &lt; 8.0 its making sound but no popup.</p>