qt: some minor icon fixes

• I recently colorized only the menus (!6693 (merged)), but it seems that menu/add.svg is used in other places as well. I try to colorize them as well.
• There is no such icon as ic_fluent_arrow_shuffle_on.svg, this is an old bug (from when fluent icons were introduced).
• There is no more eject.svg, this is an old bug (from when fluent icons were introduced).

Request review @chub.