Feature: Direct message from Statuses (#7089)

* Fix: Switching between composing direct message and mention from menus

Previously clicking "direct message" followed by "mention" resulted in the composed status staying as "direct", along with weird spacing of items in the text area. This attempts to fix that.

* Fix: Add missing proptype check for onMention in Status component

* Add the ability to send a direct message to a user from the menu on Statuses

* Add space between "Embed" and "Mention" on expanded statuses menu