Add FIT tag to spawned clothing again

Fixes #7542

Thanks to kevingranade for the hint about item spawning.

The function `map::spawn_items` didn't had that special treatment of clothing that the `map::spawn_an_item` has. The complex item groups place fully created items on on the map and can not use `map::spawn_an_item` (which accepts an item type, not a whole item), but only `map::spawn_an_item` had this special ode to create fitted clothing.