fix the directory problem when loading the map

[engyasin]

PR Summary

The 'WindowPath' object of the map .json file , would load the whole directory once again when loading the map, which render the directory wrong., like issue #102
Instead only the file name should be taken, with .name simply

Testing

The change is minimal. The tutorial notebook works now.

In order to ensure this PR works as intended, it is:

• unit tested.
• other or not applicable (additional detail/rationale required)

Compliance with Standards

As the author, I certify that this PR conforms to the following standards:

• Code changes conform to PEP8 and docstrings conform to the Google Python style guide.
• A well-written summary explains what was done and why it was done.
• The PR is adequately tested and the testing details and links to external results are included.

[benjaminrwilson]

Thanks, @engyasin!