update Notification count after notification is marked as read (commons-app#2423)

Author: cypherop

app/src/main/java/fr/free/nrw/commons/contributions/MainActivity.java

@@ -491,6 +491,12 @@ public void onRequestPermissionsResult(int requestCode,
         }
     }
 
+    @Override
+    protected void onResume() {
+        super.onResume();
+        setNotificationCount();
+    }
+
     @Override
     protected void onDestroy() {
         locationManager.unregisterLocationManager();