bpo-44342: [Enum] fix data type search (GH-26667)

In an inheritance chain of

  int -> my_int -> final_int

the data type is now final_int (not my_int)
(cherry picked from commit 3a7cccfd6cd3693e1a2ab65ee05d7f45f8501dfa)

Co-authored-by: Ethan Furman <ethan@stoneleaf.us>

Co-authored-by: Ethan Furman <ethan@stoneleaf.us>
diff --git a/Lib/enum.py b/Lib/enum.py
index 9f9c89e..49c46ea 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -823,7 +823,7 @@ def _find_data_type(bases):
                         data_types.add(candidate or base)
                         break
                     else:
-                        candidate = base
+                        candidate = candidate or base
             if len(data_types) > 1:
                 raise TypeError('%r: too many data types: %r' % (class_name, data_types))
             elif data_types: