Ignore user inputs when toggleMsgLoader is true

[gdaniel]

User inputs are still sent to the server when the bot prints the message loader, and the inputs will be handled as if they follow the message currently being printed. This may be an issue if the bot asks a question with buttons, because the user reply will be off tracks.

A simple solution would be to disable user input handling when the bot is printing the message loader.

[hamzaed]

We can disable the submit button when toggleMsgLoader is true. We should also deal with the key enter which also triggers the the submit event.

[gdaniel]

First version: disable submit / enter. We'll rethink the message loader in the future.