fix the dtype=None case

Author: rushabh-v

pandas/core/arrays/integer.py

@@ -227,9 +227,9 @@ def coerce_to_array(
             mask = mask.copy()
         return values, mask
 
-    typ = dtype.numpy_dtype()
+    typ = dtype.numpy_dtype if dtype is not None else None
     values = np.asarray(values, dtype=typ)
-    if copy and hasattr(values, 'dtype'):
+    if copy:
         values = values.copy()
 
     if is_object_dtype(values):