Fallback being called after adding bot to Skype

Original Issue: https://github.com/botman/botman/issues/969
-------------------

- BotMan Version: 2.4.1
- PHP Version: 7.3.1
- Messaging Service(s): BotFramework (Skype), Version 1.1.1
- Cache Driver: file

### Description:
When adding my Skype Bot, the defined ´fallback´ function is being called.

### Steps To Reproduce:
Add to ´routes/botman.php´.
´´´
$botman->fallback(function ($bot) {
$bot->reply('Sorry, but I did\'t understand you.');
});
´´´
Add your Skype Bot in Skype.