Attempt to fix regression in unit test

Fix the following issue:

> UnboundLocalError: cannot access local variable 'JSON' where it is
> not associated with a value

This, however, yields another problem:

```plain
>           load = CLASS_TO_LOAD_FUNC[cls]
E           KeyError: <class 'tests.unit.v1.test_union_as_type_alias_recursive.test_union_as_type_alias_recursive.<locals>.MyTestClass'>

During handling of the above exception, another exception occurred:

[…]

E   NameError: name 'JSON' is not defined
```

Author: claui

tests/unit/v1/test_union_as_type_alias_recursive.py

@@ -1,4 +1,5 @@
 from dataclasses import dataclass
+from typing import Union
 
 from dataclass_wizard import JSONWizard
 
@@ -9,7 +10,7 @@ def test_union_as_type_alias_recursive():
     Recursive or self-referential `Union` (defined as `TypeAlias`)
     types are supported.
     """
-    JSON = str | int | float | bool | dict[str, JSON] | list[JSON] | None
+    JSON = Union[str, int, float, bool, dict[str, "JSON"], list["JSON"], None]
 
     @dataclass
     class MyTestClass(JSONWizard):