Core: Prevent people from using LogicMixin incorrectly

There's a world that ran into some issues because it defined its custom LogicMixin variables at the class level.

This caused "instance bleed" when new CollectionState objects were created.

I don't think there is ever a reason to have a non-function class variable on LogicMixin without also having `init_mixin`, so this asserts that this is the case.

Tested:
Doesn't fail any current worlds
Correctly fails the world in question

Also, not gonna call out that world because it was literally my fault for explaining it to them wrong :D

worlds/AutoWorld.py

@@ -107,6 +107,11 @@ class AutoLogicRegister(type):
             elif not item_name.startswith("__"):
                 if hasattr(CollectionState, item_name):
                     raise Exception(f"Name conflict on Logic Mixin {name} trying to overwrite {item_name}")
+
+                assert callable(function) or "init_mixin" in dct, (
+                    f"{name} defined class variable {item_name} without also having init_mixin."
+                )
+
                 setattr(CollectionState, item_name, function)
         return new_class