Enhance toast alerts to include indication of time before they disappear

[gdoyle1]

High priority

Toast alerts disappear after a matter of seconds, but including some sort of animation to indicate that timing would help clarify how long they last for. This is something that came out of the animation working group that @lboehling and @fionayhlin proposed some variations for.

https://xd.adobe.com/view/b0470063-1751-48b7-68a3-6e58aaa04b46-c676/screen/2f4134f6-e7c6-47d1-a937-2fb7e8ead157?fullscreen and gif shown here https://docs.google.com/document/d/1x8IiTnYEJm183STPdTWb0fcUxMFZCA9B0atnyFezRTs/edit#heading=h.lxip9vebcms2