Allow changing "Find" and "Frame" shortcuts

Mac user - I always had cmd+F as “Frame Selection” as cmd+option+F was too slow
and delicate. I don’t use the search function nearly as much, but it took away cmd+F.

I can’t override these shortcuts as I once could, it seems “Find” can’t be overridden.

Until Figma allows full shortcut customisation, at least allow for MacOS system override.