Fix display bug in wish_item_callback

- create a new item on during the menu item callback. The constructor of item knows better how to make a new item object than this code.
- remove member tmp. It was not really used outside of the menu callback.
- remove advance_nextinv and assigning a invlet to the tmp member. That item object was not used anyway.
- move the two in_its_container calls outside of the if clause and make only once.
- use fold_and_print instead of manually printing the description
- simply clean the whole right side of the window, including the single-character column between the menu list and the item description.
- remove translation of "%s" - what was it supposed to do?
- show the "How many?" dialog only when the amount is actually going to be used.
- use the name of the granted item, instead of asking the item_controller again for the very same item.

Fixes #6703