add 'draw on screen' during screen sharing and enable the mouse to be the drawing tool by default

[sam_PTC]

unless this is a patented Slack feature, please copy 1:1 and add to Teams :) 

[#2]

Hi @sam_PTC   there's a Uservoice item on this subject that you might want to vote on: https://microsoftteams.uservoice.com/forums/555103-public/suggestions/38381215-draw-during-the-share...

[#3]

@ThereseSolimeno