default message when there is an error 400 gathered by the dialog manager

[anneliret]

Would it be possible to show in case the response is an error, a message like “there has been something wrong with your request, please restart the chatbot and try with a data instance of the appropriate format or describe what you've done in an email to hello@isee4xai.com” ?

[anjanaw]

Error message added when the chatbot is disconnected due to server errors.