[test] No longer use np.frombuffer to convert LowLevelView arrays to numpy

This was a (terrible) workaround to the fact that resulting views of multidim arrays did not convey the right itemsize based on the underlying type. Now that #21378 is fixed, the workaround breaks and we can just use `np.array(arr, dtype)` which is a lot better and Pythonic for users.

Author: aaronj0

bindings/pyroot/pythonizations/test/array_conversions.py

@@ -122,7 +122,7 @@ def test_2DArray_NumpyView(self):
         """
         for dtype in self.typemap:
             cpp_arr = self.generate_cpp_arrays(dtype[1])
-            np_obj = np.frombuffer(cpp_arr, dtype[0], count=11 * 2).reshape(11, 2)
+            np_obj = np.array(cpp_arr, dtype=dtype[0])
             self.check_shape(cpp_arr, np_obj)
             self.validate_numpy_view(np_obj, dtype)