Fix typo in test_dataclasses.py (gh-95735)


`dataclass` was called as a function when it was almost certainly intended to be a decorator.
(cherry picked from commit 59e09efe888affe549e9249f188797c1325edecc)

Co-authored-by: da-woods <dw-git@d-woods.co.uk>
diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py
index f4f7ed5..f72e81c 100644
--- a/Lib/test/test_dataclasses.py
+++ b/Lib/test/test_dataclasses.py
@@ -2129,12 +2129,12 @@ class C(B):
         self.assertEqual(c.z, 100)
 
     def test_no_init(self):
-        dataclass(init=False)
+        @dataclass(init=False)
         class C:
             i: int = 0
         self.assertEqual(C().i, 0)
 
-        dataclass(init=False)
+        @dataclass(init=False)
         class C:
             i: int = 2
             def __init__(self):