Revert "Let plugins allow/prevent the download of individual tickets in an order (#3836)"

This reverts commit e20edab98f.

src/pretix/base/ticketoutput.py

@@ -96,9 +96,6 @@ class BaseTicketOutput:
         """
         raise NotImplementedError()
 
-    def get_tickets_to_print(self, order):
-        return order.positions_with_tickets
-
     def generate_order(self, order: Order) -> Tuple[str, str, str]:
         """
         This method is the same as order() but should not generate one file per order position
@@ -119,7 +116,7 @@ class BaseTicketOutput:
         """
         with tempfile.TemporaryDirectory() as d:
             with ZipFile(os.path.join(d, 'tmp.zip'), 'w') as zipf:
-                for pos in self.get_tickets_to_print(order):
+                for pos in order.positions_with_tickets:
                     fname, __, content = self.generate(pos)
                     zipf.writestr('{}-{}{}'.format(
                         order.code, pos.positionid, os.path.splitext(fname)[1]