STYLE: remove use in pd.api.dtype in list/array.py (pandas-dev#39203)

Author: nofarmish

pandas/tests/extension/list/array.py

@@ -14,6 +14,7 @@
 
 import pandas as pd
 from pandas.core.arrays import ExtensionArray
+from pandas.api.types import is_string_dtype, is_object_dtype
 
 
 class ListDtype(ExtensionDtype):
@@ -104,9 +105,7 @@ def astype(self, dtype, copy=True):
             if copy:
                 return self.copy()
             return self
-        elif pd.api.types.is_string_dtype(dtype) and not pd.api.types.is_object_dtype(
-            dtype
-        ):
+        elif is_string_dtype(dtype) and not is_object_dtype(dtype):
             # numpy has problems with astype(str) for nested elements
             return np.array([str(x) for x in self.data], dtype=dtype)
         return np.array(self.data, dtype=dtype, copy=copy)