[Messenger] Typing indicator not being turned off after the bot sends the message

[theGBguy]

Bug Description
I followed this example messenger-typing to display typing on and typing off sender actions. The indicator is displayed but not turned off even after the message is sent. It is only turned off after 20 seconds which is default turning off period for the typing indicator.

Expected behavior
A typing indicator to be shown initially and to be dismissed when the bot sends the message.