Fix inspect(sort=False) to preserve instance attribute order

[ye-soling]

This PR fixes an issue where inspect(sort=False) did not preserve the
insertion order of instance attributes.

Previously, instance attributes were always displayed in alphabetical order
because dir(obj) returns a sorted list of attribute names. This behavior
ignored the sort=False option.

To fix this, when sort=False and the object has a __dict__, the instance
attribute insertion order is used instead of dir(obj).

A test was added to ensure the attribute order is preserved when sort=False.

[ye-soling]

Hi! Thanks for reviewing this PR 🙂
This fixes the issue where inspect(sort=False) did not preserve
instance attribute order and includes a test for the fix.
Please let me know if any changes are needed.