<% notices = flash_notices()
# static messages (i.e. ones that are present on page load) need to push
# the content down, since they don't auto-dismiss themselves. but they
# also need to be fixed so they remain visible when you scroll down so we
# put a copy of them in this hidden (but layout-ed) buffer
%>
<ul id="flash_message_buffer" aria-hidden="true">
  <%= render :partial => "shared/flash_notice", :collection => notices %>
</ul>
<ul id="flash_message_holder">
  <%= render :partial => "shared/flash_notice", :collection => notices %>
</ul>
<div id="flash_screenreader_holder" class="screenreader-only" role="alert">
</div>

<% notices = flash_notices()
# static messages (i.e. ones that are present on page load) need to push
# the content down, since they don't auto-dismiss themselves. but they
# also need to be fixed so they remain visible when you scroll down so we
# put a copy of them in this hidden (but layout-ed) buffer
%>
<ul id="flash_message_buffer" aria-hidden="true">
  <%= render :partial => "shared/flash_notice", :collection => notices %>
</ul>
<ul id="flash_message_holder">
  <%= render :partial => "shared/flash_notice", :collection => notices %>
</ul>
<div id="flash_screenreader_holder" class="screenreader-only" role="alert">
	<%= render :partial => "shared/flash_notice", :collection => notices %>
</div>

Make group flash notifications accessible for JAWS
[Accessibility] Make group flash notifications accessible for JAWS

Fixes: CNVS-12797

JAWS requires a div to exist already for it to be
accessible. The flash_screenreader_holder existed,
so adding the partial there when it's needed will
make JAWS pick it up and read it immediately.

Test-Plan:
-Use old groups by disabling new group feature flag
  in account settings of admin account
-Create a group and make sure it's set for users to
  join automatically
-Login as user and join/leave group
-Verify that notification is accessible

Change-Id: I431ebcd74b7d01dea5041b801699b0ee72ead5ea
Reviewed-on: https://gerrit.instructure.com/36183
Reviewed-by: Drew Bowman <43bd25f9469d5056946537962fe98ec04e66c401@instructure.com>
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
QA-Review: Steven Shepherd <e794458448443812fb2685675aab3bbd1a3891bc@instructure.com>
Product-Review: Jayce Higgins <8f0644d105785a923e938c7b131e3ab930cb6139@instructure.com>
