Fixes#30403.
Having tabIndex set to 0 led to keyboard focus being put on
a scrollbar container, which led to users having to tab twice
to skip a container.
This commit also removes instances of tabIndex being set to
-1 programatically for certain cases, since it is -1 by default now.
This commit also removes `outline: none` for simplebar since
that property is not needed anymore because the wrapper is
not focusable anymore.
This commit updates the user group popovers to change the icon
and text of ".manage-group" option to match what we have in
gear menu and also change the heading and ".manage-group"
option to be left-aligned.
We now add a "Group settings" option in the gear menu to open
the new "#groups" UI and the "Manage group" option in user
group popover also opens the new UI.
Shubham Padia
CIC4DA
Sahil Batra
Aman Agrawal