replace dtype in with is_string_dtype

Author: Nikoleta-v3

pandas/core/dtypes/cast.py

@@ -1222,7 +1222,7 @@ def construct_1d_arraylike_from_scalar(value, length, dtype):
         # coerce if we have nan for an integer dtype
         if is_integer_dtype(dtype) and isna(value):
             dtype = np.dtype('float64')
-        if isinstance(dtype, np.dtype) and dtype.kind in ("U", "S"):
+        if isinstance(dtype, np.dtype) and is_string_dtype(dtype):
             subarr = np.empty(length, dtype=object)
             if not isna(value):
                 value = to_str(value)