In this commit, we update the UI to:
* Display emoji on the buddy list (right side sidebar).
* Display the emoji picker on the set status overlay.
It also updates the `z-index` of
`#set_user_status_modal`, which was changed from 105
to 1050 in 166bfa4cf8. We change it back to 105, so
emoji-popover can be visible on top of the
`#set_user_status_modal`.
We also remove the `tabindex` property from the
`#set_user_status_modal` so it can allow keyboard
events for emoji popover.
This also migrates from loading the modal dynamically rather than
statically once at page initialization.
With styling changes by tabbott to preserve the original look of the
UI.
Fixes#18278.