Minimizable sample should not reconnect

[Karim-khadro]

Direct line reconnects to the bot framework after minimiz and maximiz the bot window in the browser

• The impact :
  The user will receive a welcome message after every time he changes the window size

• Test environment:
  1- Download the minimizable web chat example
  2- Then update web chat from 4.5.1 to 4.6.0
  3- After reciving the welcome message from the bot click on minimz button then click on maximiz button

• Please find below the screenshot attached for reference.
  First connection
  

After minimiz and maximiz the window

Web chat version 4.6.0

[cwhitten]

@corinagum can you please take a look at this?

[tdurnford]

The sample dispatches a backcahnnel welcome event on each DIRECT_LINE/CONNECT_FULFILLED action which is triggered each time the chat window is expanded. We should add a state variable to track if the backchannel welcome event has already been triggered before we send it to the bot.

[corinagum]

I'll try to patch this up tonight.

[corinagum]

@compulim told me he's going to be making changes to this sample over the next week for ic3 work, so I will reassign this to him.

[compulim]

Will work on this later today.

[compulim]

@karimkhadro96 we are fixing it in #2758.

This is not an ideal fix. I opened a discussion issue #2750 and resolving it would unblock the ideal fix.

As #2750 described, we can't mount/unmount Web Chat without connect/disconnect Direct Line. So currently, we can only hide Web Chat but not releasing the memory.

There are few hacks, but I would prefer to resolve the bug in an ideal way.