Add missing fill_with_flags decorator to InviteFlags class

Author: Sacul0457

discord/flags.py

@@ -2400,6 +2400,7 @@ def content_inventory_entry(self):
         return 1 << 5
 
 
+@fill_with_flags()
 class InviteFlags(BaseFlags):
     r"""Wraps up the Discord Invite flags