R1:59678094fb77

Refactor PhabricatorBadgesEditRecipientsController to remove dead code

Summary: `$form` in `$dialog = id(new AphrontDialogView())->appendForm($form)` is only defined when `if ($can_edit)` was `true` beforehand. But that was always true. Thus add a variable definition (and remove some unused variables like `$form_box`).

Test Plan:
Visit the page /badges/recipients/1/ or also directly /badges/recipients/1/add/ and add some recipients. It still works as before.

Visit the page without enough permissions. It…