codefactor.io \(o.o)/ also one unnecessary semicolon
Implements IHasAccentColour for conformity to rest of project. Also fixes a nullref when opening the login menu.
This also - Renames TextAwesome to SpriteIcon. - Removes the default size of "20" from SpriteIcon (now defaults to the underlying texture size).
Depends on https://github.com/ppy/osu-framework/pull/837