Zillion: use "new" settings api and cleaning (#3903)

* Zillion: use "new" settings api and cleaning

* python 3.10 typing update

* don't separate assignments of item link players

worlds/zillion/test/__init__.py

@@ -1,4 +1,3 @@
-from typing import cast
 from test.bases import WorldTestBase
 from .. import ZillionWorld
 
@@ -13,8 +12,9 @@ class ZillionTestBase(WorldTestBase):
         This makes sure that gun 3 is required by making all the canisters
         in O-7 (including key word canisters) require gun 3.
         """
-        zz_world = cast(ZillionWorld, self.multiworld.worlds[1])
-        assert zz_world.zz_system.randomizer
-        for zz_loc_name, zz_loc in zz_world.zz_system.randomizer.locations.items():
+        z_world = self.multiworld.worlds[1]
+        assert isinstance(z_world, ZillionWorld)
+        assert z_world.zz_system.randomizer
+        for zz_loc_name, zz_loc in z_world.zz_system.randomizer.locations.items():
             if zz_loc_name.startswith("r15c6"):
                 zz_loc.req.gun = 3